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SYSTEMTAP EXAMPLES INDEX (see also keyword-index.txt) For systemtap version 4.0. apps/gmalloc_watch.stp - Tracing glib2 memory allocations keywords: trace The gmalloc_watch.stp script from Colin Walters' blog (https://blog.verbum.org/2011/03/19/analyzing-memory-use-with-systemt ap/) traces the allocation of glib2 memory using the markers in glib2. # stap gmalloc_watch.stp -T 1 apps/libguestfs_log.stp - Trace libguestfs startup keywords: application trace The libguestfs_log.stp script prints a log of when various libgueststartup steps are encountered. The first column is microseconds since the script started. The second column is the time elapsed in microseconds between the previous and current events and the third column is the event name. # stap libguestfs_log.stp -T 1 apps/php-trace.stp - Tracing of PHP code execution keywords: trace Trace of executing PHP code using the enabled markers. # stap php-trace.stp -c 'php -f hello.php' apps/stap_time.stp - Provide elapsed times for Passes of SystemTap script compilation keywords: application trace SystemTap has multiple passes to convert the text of a SystemTap script into instrumentation that actually collect data on the system. The stap_time.stp script uses the markers in SystemTap to note the amount of time that each of the passes requires. When SystemTap completes pass 4 (compiling the instrumentation into a kernel module) the script print out the script name followed by the amount of time in milliseconds required for Pass 0 (command line option parsing), Pass 1 (script parsing), Pass 2 (elaboration), Pass 3 (code generation), and Pass 4 (module compilation). The resulting data can be analyzed to determine if there are issues with the amount of time that systemtap takes to generate instrumentation. # stap stap_time.stp -T 1 general/alias_suffixes.stp - Count I/O Syscalls using Alias Suffixes keywords: io statistics alias_suffixes.stp is a demonstration of how alias suffixes in the systemtap language might be used. The script tracks the wall clock time for each invocation of the system calls open, close, read, and write. When the script exists it prints out the minimum, average, and maximum times in microseconds for each system call, followed by a count of times that each syscall was invoked and a histogram showing the distributions of times. # stap alias_suffixes.stp -T 1 general/also_ran.stp - Keep a tally of executables run on the system keywords: prometheus The also_ran.stp script tallies each time a executable is started or a shared library is loaded for execution. This information can be useful to determine what software is actually being used on the system. The script makes the information available via procfs in Prometheus readable format. # stap also_ran.stp -T 1 general/ansi_colors.stp - Color Table for ansi_set_color() keywords: format The script prints a table showing the available color combinations for the ansi_set_color() function in the ansi.stp tapset. # stap ansi_colors.stp general/ansi_colors2.stp - Show Attribues in Table for ansi_set_color() keywords: format The script prints a table showing the available attributes (bold, underline, and inverse) with color combinations for the ans_set_color() function in the ansi.stp tapset. # stap ansi_colors2.stp general/badname.stp - Bad Filename Filter keywords: filesystem guru The badname.stp script shows how one could prevent the creation of files with undesirable names using guru mode. # stap -g badname.stp -c "touch /tmp/myXXXbadnameXXXfile.$$ 2>&1 | grep \ denied" general/callgraph.stp - Callgraph Tracing keywords: simple trace callgraph Print a timed per-thread microsecond-timed nested callgraph. The first parameter names the function probe points to trace. # stap callgraph.stp 'kernel.function("*@fs/proc*.c")' -c "cat \ /proc/sys/vm/* || true" general/cpu_throttle.stp - Monitor Intel processors for throttling due to power or thermal limits keywords: prometheus limits Intel processors have hardware mechanisms that will reduce the effective processors speed to avoid exceeding set thermal or power constraints. The cpu_throttle.stp script monitors when CPU throttling occurs and accumulates the amount of time in milliseconds that each processor is throttled. The script makes the information available via procfs in Prometheus readable format. # stap cpu_throttle.stp -T 1 general/eventcount.stp - Interactive Count Specified Events keywords: interactive statistics thread process The script periodically prints a count of specified events and their related tid's over the course of execution. Numerous configuration options exist to control filtering / reporting, some of which can be modified at runtime. See the script source for more information. # stap eventcount.stp 'syscall_any' -c 'sleep 3' general/func_time_stats.stp - Function Time Statistics keywords: function statistics The func_time_stats.stp script tracks the wall clock time for each invocation of the function probe listed as the first command line argument. When the script exits it prints out the minimum, average, and maximum times in microseconds followed by a count of times that the function was called and a histogram showing the distributions of times. # stap func_time_stats.stp 'syscall.read' -T 1 general/graphs.stp - Graphing Disk and CPU Utilization with gnuplot keywords: monitoring The script tracks the disk and CPU utilization. It prints a stream of data which, when piped directly into gnuplot, draws historical curves for each. # stap graphs.stp -T 1 general/helloworld.stp - SystemTap "Hello World" Program keywords: _best simple A basic "Hello World" program implemented in SystemTap script. It prints out "hello world" message and then immediately exits. # stap helloworld.stp general/key.stp - make keyboard noises keywords: simple For fans of Leroy Anderson and Typewriters only, this script arranges to play a click or a zing for various keystrokes. # stap key.stp -c 'sleep 5' general/keyhack.stp - Hack the keyboard keywords: simple guru This script makes it appear that one's keyboard is broken, by changing keycodes at the kernel device driver level. Annoy your friends! # stap -g keyhack.stp -c 'sleep 5' general/measureinterval.stp - Measure intervals between events keywords: monitoring The measureinteval.stp script allows quick creation of instrumentation to measure quantity between different probe points, aggregate the measurements, and display the results. The first argument to the script is the quantity to measure such as time in microseconds via "gettimeofday_us()". There could be multiple intervals being measured concurrently and the second argument is the means to match the start probe points listed in the fourth argument with the end probes listed in the fifth argument. The third argument is how to display the aggregated data. The data could be displayed as a sum (@sum), an average (@avg), or a histogram (@hist_log). The fourth and fifth arguments are lists of probes marking the start and end of an interval. An optional sixth argument allows grouping of the intervals. One could use "tid()" for the matching argument to measure the intervals on a per-thread basis, but then use "execname()" for the optional argument to group the measurements by executable name. If there is no sixth argument, all the intervals are aggregated into a single entry. # stap measureinterval.stp "gettimeofday_us()" "tid()" @sum vm.pagefault \ vm.pagefault.return "execname()" -c 'sleep 3' general/para-callgraph-verbose.stp - Callgraph Tracing with Verbose Arguments keywords: trace callgraph Print a timed per-thread microsecond-timed callgraph, complete with pretty-printed function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger. # stap para-callgraph-verbose.stp 'kernel.function("*@fs/proc*.c")' \ 'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true" general/para-callgraph.stp - Callgraph Tracing with Arguments keywords: _best trace callgraph Print a timed per-thread microsecond-timed callgraph, complete with function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger. # stap para-callgraph.stp 'kernel.function("*@fs/proc*.c")' \ 'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true" general/py2example.stp - SystemTap python 2 support tapset keywords: simple A python support tapset that displays backtraces and variable values # stap -I tapset -c '/usr/bin/python2 pyexample.py 35' py2example.stp general/py3example.stp - SystemTap python 3 support tapset keywords: simple A python support tapset that displays backtraces and variable values # stap -g --suppress-time-limits -I tapset -c '/usr/bin/python3 \ pyexample.py 35' py3example.stp general/regex.stp - Report opened files whose names match a given regex keywords: regex Uses the regex functionality to detect opened files whose names match a pattern given on the command line. If no command line parameter is given, demonstrate by filtering for files that end with an extension showing them to be an archive. # stap regex.stp -T 1 general/sizeof.stp - Print the Size of a C Type keywords: statistics memory This script prints the size of a type, based on dwarf debuginfo for any kernel or userspace module, or trial-compilation of a given header file name. # stap sizeof.stp FILE '</usr/include/stdio.h>' general/sizeof_interactive.stp - Interactive Print the Size of a C Type keywords: statistics memory interactive This script prints the size of a type, based on dwarf debuginfo for any kernel or userspace module, or trial-compilation of a given header file name. Types and corresponding locations are provided to the script at runtime via keyboard input. The format of the input is identical to that of sizeof.stp (see script source for more information). Types and locations can be repeatedly given until the process is terminated. # echo "FILE '</usr/include/stdio.h>'" | stap sizeof_interactive.stp -T 1 general/socket-events.stp - Trace Socket Activity of a Process keywords: socket syscall Prints the life cycle of all sockets associated with a process. This includes bytes and timing. The timing information that is tracked includes event completion relative to the start of said event and the end of the previous event. Currently tracks read, write, recv, send, connect and close. # stap socket-events.stp general/stopwatches.stp - See the amount of wall clock time a process spends in various states keywords: time The stopwatch.stp script illustrates how to use multiple stopwatches record how much wallclock time a process spends in kernel- and user-space. On exit the script prints out the time in seconds, milliseconds, microseconds, and nanoseconds. Note that this output of this script is not directly comparable to the time command because time records the time that the process is actually active in kernel- and user-space. # stap stopwatches.stp -T 1 general/tcl-funtop.stp - Profile Tcl calls keywords: profiling The tcl-funtop.stp script displays a top-like view of most frequently used Tcl functions for the each five second interval. # stap tcl-funtop.stp -T 5 general/tcl-trace.stp - Callgraph Tracing of Tcl code keywords: callgraph Print a timed per-thread microsecond-timed callgraph of executing Tcl code. # stap tcl-trace.stp -T 5 general/varwatch.stp - Watch a Variable Changing Value in a Thread keywords: _best monitoring This script places a set of probes (specified by $1), each of which monitors the state of some context $variable expression (specified by $2). Whenever the value changes, with respect to the active thread, the event is traced. # stap -w varwatch.stp 'kernel.statement("do_sys_open@fs/open.c:*")' \ '$$vars' -T 1 general/watchdog.stp - Watchdog Timer for Arbitrary Events keywords: watchdog backtrace The watchdog.stp script provides a watchdog timer mechanism for arbitrary events. The script takes three arguments: the events to start watchdog timer, the event to stop the watchdog timer, and the time in millseconds for the watchdog. If the watchdog timer is exceed, the script will trigger a stack backtrace of the user-process that timed out using pstack. This script can be used to diagnose what the userspace application is doing when a slower than expected operation occurs. # stap watchdog.stp 'syscall.nanosleep' 'syscall.nanosleep.return' 1000 \ -T 1 general/whythefail.stp - Why did the function fail? keywords: speculation monitoring function trace _best The whythefail.stp script prints a statement-execution trace for a given function, but only for those runs of the function that ended up with a (configurable) post-return condition. # stap whythefail.stp kernel do_sys_open '$return < 0' -c 'cat \ /root/no-such-file || true' interrupt/interrupts-by-dev.stp - Record Interrupts on a Per-Device Basis keywords: interrupt The interrupts-by-dev.stp script profiles interrupts received by each device per 100 ms. # stap interrupts-by-dev.stp -T 1 interrupt/scf.stp - Tally Backtraces for Inter-Processor Interrupt keywords: interrupt backtrace The Linux kernel function smp_call_function causes expensive inter-processor interrupts (IPIs). The scf.stp script tallies the processes and backtraces causing the interprocessor interrupts to identify the cause of the expensive IPI. On exit the script prints the tallies in descending frequency. # stap scf.stp -T 1 io/capture_ssl_master_secrets.stp - Capture SSL/TLS master secrets from gnutls and openssl users keywords: io monitoring Capture SSL/TLS master secrets from gnutls and openssl users for easy traffic decryption # stap capture_ssl_master_secrets.stp -c 'sleep 3' io/deviceseeks.stp - Histograms of Seek Behavior for Each Device keywords: disk The deviceseeks.stp script generates a periodic histogram showing the frequency of different sized seeks (in sectors) on each device, or optional given device-name regexp # stap deviceseeks.stp -T 1 sda io/disktop.stp - Summarize Disk Read/Write Traffic keywords: disk Get the status of reading/writing disk every 5 seconds, output top ten entries during that period. # stap disktop.stp -T 1 io/eatmydata.stp - disable fsync keywords: io guru simple Suppresses fsync() syscalls from processes identified by stap -c/-x by turning them into presumed-faster fsync() on some dummy or other file descriptor # stap -g eatmydata.stp -c 'strace ls || true' io/enospc.stp - Report an disk out-of-space condition. keywords: disk filesystem This script monitors a filesystem implementations for early internal indications of ENOSPC, and reports these to the system logger and the systemtap console. # stap enospc.stp -T 1 io/inodewatch.stp - Monitoring Reads and Writes to a File keywords: io The inodewatch.stp outputs the executable name and process id each time a read or write occurs to the specified inode on the specified major/minor device. # stap inodewatch.stp 0x08 0x01 100 -T 1 io/inodewatch2.stp - Monitoring Attribute Changes to a File keywords: io The inodewatch2.stp script outputs the executable name, process id, and attributes each time the attributes are changed on the specified inode on the specified major/minor device. # stap inodewatch2.stp 0x08 0x01 100 -T 1 io/io_submit.stp - Tally Reschedule Reason During AIO io_submit Call keywords: io backtrace When a reschedule occurs during an AIO io_submit call, accumulate the traceback in a histogram. When the script exits prints out a sorted list from most common to least common backtrace. # stap io_submit.stp -T 1 io/ioblktime.stp - Average Time Block IO Requests Spend in Queue keywords: io The ioblktime.stp script tracks the amount of time that each block IO requests spend waiting for completion. The script computes the average waiting time for block IO per device and prints list every 10 seconds. In some cases there can be too many outstanding block IO operations and the script may exceed the default number of MAXMAPENTRIES allowed. In this case the allowed number can be increased with "-DMAXMAPENTRIES=10000" option on the stap command line. # stap ioblktime.stp -T 1 io/iodevstats.stp - List Executables Reading and Writing the Most Data by Device keywords: io profiling The iodevstats.stp script measures the amount of data successfully read and written by all the executables for each io device on the system. The output is sorted from greatest sum of bytes read and written to a device by an executable to the least. The output contains device major/minor number, the count of operations (reads and writes), the totals and averages for the number of bytes read and written. # stap iodevstats.stp -T 1 io/iostat-scsi.stp - IO Statistics for SCSI Devices keywords: io profiling scsi The iostat-scsi.stp script provides a breakdown of the number of blks read and written on the machine's various SCSI devices. The script takes one argument which is the number of seconds between reports. # stap -g iostat-scsi.stp 1 -T 1 io/iostats.stp - List Executables Reading and Writing the Most Data keywords: io profiling The iostat.stp script measures the amount of data successfully read and written by all the executables on the system. The output is sorted from most greatest sum of bytes read and written by an executable to the least. The output contains the count of operations (opens, reads, and writes), the totals and averages for the number of bytes read and written. # stap iostats.stp -T 1 io/iotime.stp - Trace Time Spent in Read and Write for Files keywords: profiling syscall io file The script watches each open, close, read, and write syscalls on the system. For each file the scripts observes opened it accumulates the amount of wall clock time spent in read and write operations and the number of bytes read and written. When a file is closed the script prints out a pair of lines for the file. Both lines begin with a timestamp in microseconds, the PID number, and the executable name in parentheses. The first line with the "access" keyword lists the file name, the attempted number of bytes for the read and write operations. The second line with the "iotime" keyword list the file name and the number of microseconds accumulated in the read and write syscalls. # stap iotime.stp -T 1 io/iotop.stp - Periodically Print IO Activity by Process Name keywords: io Every five seconds print out the top ten executables generating I/O traffic during that interval sorted in descending order. # stap iotop.stp -T 1 io/mbrwatch.stp - Monitor Read/Write of the Boot Sector Area of Block Devices keywords: io monitoring disk simple The mbrwatch.stp script reports any attempted reads/writes of the first few sectors of a raw block device. # stap mbrwatch.stp -c "dd of=/dev/null count=1 if=/dev/`grep -v major \ /proc/partitions | grep . | grep -v 'sr[0-9]' | awk '{print $4}' | \ head -1`" io/nfs_func_users.stp - Tally the Number of NFS Functions Used by Each Process keywords: io profiling The nfs_func_users.stp script counts the uses of NFS functions in the kernel on a per process bases. The output is sorted from the process with the greatest number of NFS functions called to the least. The output contains the executable name, the process number, and the total number of NFS functions called by the process. # stap nfs_func_users.stp -T 1 io/slowvfs.stp - Trace slow vfs opens. keywords: io simple This script prints a line for every kernel vfs_open operation that takes longer than a configurable number of microseconds. Highly contended or remote filesystems are likelier to hit this. # stap slowvfs.stp -G sloth=10 -c 'find /proc >/dev/null || true' io/switchfile.stp - Switch log files keywords: io Every second print a log message and switch log files every 5 seconds. # stap -o /tmp/switchfile.stp.out switchfile.stp -T 8 io/traceio.stp - Track Cumulative IO Activity by Process Name keywords: io Every second print out the top ten executables sorted in descending order based on cumulative I/O traffic observed. # stap traceio.stp -T 1 io/traceio2.stp - Watch IO Activity on a Particular Device keywords: io Print out the executable name and process number as reads and writes to the specified device occur. # stap traceio2.stp 0x0801 -T 1 io/ttyspy.stp - Monitor TTY Typing keywords: io tty monitoring guru The ttyspy.stp script uses tty_audit hooks to monitor recent typing activity on the system, printing a scrolling record of recent keystrokes, on a per-tty basis. # stap --skip-badvars -g ttyspy.stp -T 1 locks/bkl.stp - Tracing Contention on Big Kernel Lock keywords: locking The bkl.stp script can help determine whether the Big Kernel Lock (BKL) is causing serialization on a multiprocessor system due to excessive contention of the BKL. The bkl.stp script takes two arguments. The first one is optional, and used to enable backtraces, and print them once a process has been holding the BKL for a user specified number of nseconds is reached. The second option is compulsory and is the number of processes waiting for the Big Kernel Lock (BKL). When the number of processes waiting for the BKL is reached or exceeded, the script will print a time stamp, the number of processes waiting for the BKL, the holder of the BKL, and the amount of time the BKL was held. If backtraces are enabled, a backtrace will be printed as well. # stap bkl.stp -T 1 1 locks/bkl_stats.stp - Per Process Statistics on Big Kernel Lock Use keywords: locking The bkl_stats.stp script can indicate which processes have excessive waits for the Big Kernel Lock (BKL) and which processes are taking the BKL for long periods of time. The bkl_stats.stp script prints lists of all the processes that require the BKL. Every five seconds two tables are printed out. The first table lists the processes that waited for the BKL followed by the number of times that the process waited, the minimum time of the wait, the average and the maximum time waited. The second table lists has similar information for the time spent in holding the lock for each of the processes. # stap bkl_stats.stp -T 1 lwtools/accept2close-nd.stp - Show socket lifespan, from accept() to close() (non-debuginfo) keywords: network socket This traces socket duration from the accept() syscall to close(), and provides details on the lifespan of these passive connections, showing the distribution as a histogram. # stap accept2close-nd.stp -T 1 lwtools/biolatency-nd.stp - Measure block I/O latency distribution (non-debuginfo) keywords: io This measures block I/O latency (storage I/O, ie, disk I/O), and shows the distribution as a histogram. This can be useful to identify the characteristics of I/O latency, beyond the averages shown by iostat(1). For example, to study I/O latency outliers, or multi-modal distributions. # stap biolatency-nd.stp 1 1 lwtools/bitesize-nd.stp - Measure block I/O size distribution (non-debuginfo) keywords: io This uses the kernel tracepoint block_rq_insert to read the size of I/O. The output includes the name of the process or thread that was on-CPU when the I/O request was inserted on the issue queue. # stap bitesize-nd.stp -T 1 lwtools/execsnoop-nd.stp - Trace process exec() with command line argument details (non-debuginfo) keywords: io This can identify if CPU is consumed by short-lived processes, by tracing new process execution. It works by tracing exec() from the fork()->exec() sequence, which means it will not catch new processes that only fork(). It will also show every exec(), including those if a process re-execs. # stap execsnoop-nd.stp -T 1 lwtools/fslatency-nd.stp - Measure the distribution of file system synchronous read and write latency (non-debuginfo) keywords: io filesystem This dynamically traces two common file system functions: do_sync_read() and do_sync_write(), and reports a histogram distribution of latency. Many, but not all, file systems and workloads use these functions. Tracing their time provides one view of suffered file system latency. # stap fslatency-nd.stp 1 1 lwtools/fsslower-nd.stp - Trace slow file system synchronous reads and writes (non-debuginfo) keywords: io filesystem This dynamically traces two common file system functions: do_sync_read() and do_sync_write(), and shows details of each call that is slower than a threshold. Many, but not all, file systems and workloads use these functions. Tracing their time provides one view of suffered file system latency. # stap fsslower-nd.stp -T 1 lwtools/killsnoop-nd.stp - Trace kill() signals showing process and signal details (non-debuginfo) keywords: io This traces signals system-wide, including those sent by the kill(1) command, and shows various details. # stap killsnoop-nd.stp -T 1 lwtools/opensnoop-nd.stp - Trace open() syscalls showing filenames (non-debuginfo) keywords: io This traces the open() syscall system-wide, to show which files are being opened, and by who. # stap opensnoop-nd.stp -T 1 lwtools/rwtime-nd.stp - Summarize read() and write() syscall latency (non-debuginfo) keywords: io This traces read() and write() syscalls, producing a histogram summary of their durations (aka latencies). # stap rwtime-nd.stp -T 1 lwtools/syscallbypid-nd.stp - Count syscalls with process details (non-debuginfo) keywords: io This traces syscalls system-wide, and produces a summary report showing their counts by process ID, process name, and syscall types. # stap syscallbypid-nd.stp -T 1 memory/glibc-malloc.stp - Overview glibc malloc internal operations keywords: memory process This script reports on internal statistics of the glibc malloc implementation, as used by a process restricted by stap -x/-c # stap glibc-malloc.stp -c 'stap --dump-functions' memory/hugepage_clear_delays.stp - Summarize the time each process spends clearing huge pages keywords: memory When a huge page is initially used by a process it must be cleared of its original contents to avoid leaking information between processes. On x86_64 machines the huge pages are 2MB in size, 512 times larger than a normal 4KB page. Thus, clearing a huge page can delay program execution by a hundred or more microseconds and maybe noticeable to latency sensitive programs. This script will tally the number of times that each process triggers a huge page clear, the total time in microseconds spent clearing the pages, and the average time in microseconds of the huge page clear. # stap hugepage_clear_delays.stp -T 1 memory/hugepage_collapse.stp - Log the kernel collapsing normal pages into a huge page keywords: memory The kernel may attempt to group many normal sized pages into a single huge page to improve TLB performance. This operation may take a significant amount of time and affect program performance. You can identify if huge page collapse operations are occurring with the systemtap hugepage_collapse.stp script. # stap hugepage_collapse.stp -T 1 memory/hugepage_cow_delays.stp - Summarize the time each process spends doing copy on write for huge pages keywords: memory The system may attempt to reduce memory use by having two or more difference processes share the same writeable page in memory. However, when one of the processes write to shared page that is marked copy on write (COW) the page must be duplicated and then modified. On x86_64 machines the huge pages are 2MB in size, 512 times larger than a normal 4KB page. Thus, copy on write operation on a huge page can delay program execution by a hundred or more microseconds and maybe noticeable to latency sensitive programs. This script will tally the number of times that each process triggers a huge page copy on write, the total time in microseconds spent copying the pages, and the average time in microseconds of the huge page copy. # stap hugepage_cow_delays.stp -T 1 memory/hugepage_split.stp - Log the kernel splitting huge pages into normal sized pages keywords: memory Because some portions of the kernel code only work with normal-sized pages the kernel may convert a huge page into a set of normal-sized pages using a split operation. This operation may be relatively expensive and noticeable to latency sensitive programs. You can identify if split operations are occurring with the systemtap hugepage_split.stp script. # stap hugepage_split.stp -T 1 memory/hw_watch_addr.stp - Watch a Kernel Address Using Breakpoint Hardware keywords: memory watchpoint The script will watch accesses to a single kernel address and prints a traceback each time the address is accessed. This script needs to be run as root to allow access to the breakpoint hardware. # stap --all-modules hw_watch_addr.stp 0x`grep "vm_dirty_ratio" \ /proc/kallsyms | awk '{print $1}'` -T 5 memory/hw_watch_sym.stp - Watch a Kernel Symbol Using Breakpoint Hardware keywords: memory watchpoint The script will watch accesses to the starting address of a single kernel symbol and prints a traceback each time the symbol is accessed. This script needs to be run as root to allow access to the breakpoint hardware. # stap --all-modules hw_watch_sym.stp vm_dirty_ratio -T 5 memory/kmalloc-top - Show Paths to Kernel Malloc Invocations keywords: memory The kmalloc-top perl program runs a small systemtap script to collect stack traces for each call to the kmalloc function and counts the time that each stack trace is observed. When kmalloc-top exits it prints out sorted list. The output can be filtered to print only the first N stack traces (-t), stack traces with a minimum counts (-m), or exclude certain stack traces (-e). # ./kmalloc-top -c "sleep 1" memory/last_100_frees.stp - Log recent free(3) calls. keywords: memory process backtrace This script reports on the last few free(3) libc calls done by processes (possibly restricted by stap -x/-c), along with a userspace backtrace at those moments. # stap last_100_frees.stp -c "stap -V" -d `which stap` --ldd memory/mmanonpage.stp - Track Virtual Memory System Actions on Anonymous Pages keywords: memory The mmanonpage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, user space frees, page ins, copy on writes and unmaps for anonymous pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. This script displays the anonymous page statistics for each process that ran while the script is active. It's useful in debugging leaks in the anonymous regions of a process. # stap mmanonpage.stp -T 1 memory/mmfilepage.stp - Track Virtual Memory System Actions on File Backed Pages keywords: memory The mmfilepage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, copy on writes mapping, and unmapping operations for file backed pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. The mmfilepage.stp script is useful in debugging leaks in the mapped file regions of a process. # stap mmfilepage.stp -T 1 memory/mmreclaim.stp - Track Virtual Memory System Page Reclamation keywords: memory The mmreclaim.stp script uses the virtual memory tracepoints available in some kernels to track page reclaim activity that occurred while the script was running. It's useful in debugging performance problems that occur due to page reclamation. # stap mmreclaim.stp -T 1 memory/mmwriteback.stp - Track Virtual Memory System Writing to Disk keywords: memory The mmwriteback.stp script uses the virtual memory tracepoints available in some kernels to report all of the file writebacks that occur form kupdate, pdflush and kjournald while the script is running. It's useful in determining where writes are coming from on a supposedly idle system that is experiencing unexpected IO. # stap mmwriteback.stp -T 1 memory/numa_faults.stp - Summarize Process Misses across NUMA Nodes keywords: memory numa The numa_faults.stp script tracks the read and write pages faults for each process. When the script exits it prints out the total read and write pages faults for each process. The script also provide a break down of page faults per node for each process. This script is useful for determining whether the program has good locality (page faults limited to a single node) on a NUMA computer. # stap numa_faults.stp -T 1 memory/overcommit.stp - Log Failed Process Memory Allocation Due to Overcommit Limits keywords: memory limits The overcommit.stp script prints a line each time the kernel refuses a memory allocation request from a process because of /proc/sys/vm/overcommit* limits. # stap overcommit.stp -T 1 memory/pfaults.stp - Generate Log of Major and Minor Page Faults keywords: memory The pfaults.stp script generates a simple log for each major and minor page fault that occurs on the system. Each line contains a timestamp (in microseconds) when the page fault servicing was completed, the pid of the process, the address of the page fault, the type of access (read or write), the type of fault (major or minor), and the elapsed time for page fault. This log can be examined to determine where the page faults are occurring. # stap pfaults.stp -T 1 memory/vm.tracepoints.stp - Collect Slab Allocation Statistics keywords: memory statistics The script will probe all memory slab/slub allocations and collects information about the size of the object (bytes requested) and user-space process in execution. When run over a period of time, it helps to correlate kernel-space memory consumption owing to user-space processes. # stap vm.tracepoints.stp -T 10 network/autofs4.stp - Watch autofs4 Operations keywords: network nfs Trace key autofs4 operations such as mounting or unmounting remote filesystems. # stap autofs4.stp -T 1 network/connect_stat.stp - Show Process Ancestry for IP Connections keywords: network socket process The connect_stat.stp script prints a task's entire ancestry (parent process name/uid/gid) whenever it attempts an outgoing socket connection to a given IP address. # stap connect_stat.stp 127.0.0.1 -T 1 network/dropwatch.stp - Watch Where Socket Buffers Are Freed in the Kernel keywords: network tracepoint socket Every five seconds the dropwatch.stp script lists the number of socket buffers freed at locations in the kernel. # stap dropwatch.stp -T 1 network/net_xmit_json.stp - Tracks time between packet queue and transmit. keywords: network statistics json This script tracks time between packet queue and transmit. The information is provided to userspace via procfs in JSON format. # stap net_xmit_json.stp -T 1 network/netdev.stp - Trace Activity on Network Devices keywords: network traffic The netdev.stp script traces configuration and transmit/receive activity on network devices. # stap netdev.stp -T 1 network/netfilter_drop.stp - System-Wide Network Packet Dropping Tool keywords: network packets guru The script drops the specified number of packets of the specified protocol. Valid protocols are TCP, UDP, or ALL. If ALL is specified, all incoming packets are dropped. The number of packets to drop can be specified with a positive integer. A value of 0 indicates that packets should be dropped until the user manually exits. # stap -g netfilter_drop.stp TCP 1 -T 2 network/netfilter_summary.stp - System-Wide Count of Network Packets by IPs keywords: _best network traffic The script watches all IPv4 network traffic on the system. On exit the script prints a list showing the number of packets sent along source IP address / destination IP address pair encountered, and the total number of bytes sent among the pair. The list is ordered from greatest to least number of packets seen among the source/destination pairs. # stap netfilter_summary.stp -T 1 network/netfilter_summary_json.stp - System-Wide Count of Network Packets by IPs keywords: _best network traffic json The script watches all IPv4 network traffic on the system. The data is output in JSON format and includes the number of packets sent along source IP address / destination IP address pair encountered, and the total number of bytes sent among the pair. # stap netfilter_summary_json.stp -T 1 network/nettop.stp - Periodic Listing of Processes Using Network Interfaces keywords: network traffic Every five seconds the nettop.stp script prints out a list of processed (PID and command) with the number of packets sent/received and the amount of data sent/received by the process during that interval. # stap nettop.stp -T 1 network/nfsd-recent.stp - Keep track of NFS server statistics keywords: nfs statistics This script tracks all nfsd server operations by client_ip address, and periodically lists those clients that have made recent requests. It's a way of finding out which nfs clients might be considered still connected. # stap nfsd-recent.stp -T 1 network/nfsd-trace.stp - Trace NFSD requests with file names. keywords: nfs trace This script traces all nfsd server operations by client_ip address, operation, and complete file name (if possible). # stap nfsd-trace.stp -T 1 network/nfsd_unlink.stp - Find Which Client Is Removing NFS Files on Server keywords: nfs disk The nfsd_unlink.stp script lists the ip address and file name each time time a file is being removed or unlinked by the nfsd. This script is run on the nfs server. # stap nfsd_unlink.stp -T 1 network/nfsdtop.stp - Keep track of NFS server statistics keywords: nfs statistics The nfsdtop.stp script gathers and displays NFS lookups, # stap nfsdtop.stp -T 1 network/packet_contents.stp - Network packet contents keywords: network traffic The packet_contents.stp script displays the length of each network packet and its contents in both hexadecimal and ASCII. Systemtap strings are MAXSTRINGLEN in length by default which may not be enough for larger packets. In order to print larger packets, this limit can be increased by passing in the "-DMAXSTRINGLEN=65536" command line option. # stap packet_contents.stp -T 1 network/sk_stream_wait_memory.stp - Track Start and Stop of Processes Due to Network Buffer Space keywords: network tcp process The sk_stream-wait_memory.stp prints a time stamp, executable, and pid each time a process blocks due to the send buffer being full. A similar entry is printed each time a process continues because there is room in the buffer. # stap sk_stream_wait_memory.stp -T 1 network/socket-trace.stp - Trace Functions Called in Network Socket Code keywords: network socket The script instruments each of the functions in the Linux kernel's net/socket.c file. The script prints out trace data. The first element of a line is time delta in microseconds from the previous entry. This is followed by the command name and the PID. The "->" and "<-" indicates function entry and function exit, respectively. The last element of the line is the function name. # stap socket-trace.stp -T 1 network/socktop - Periodically Summarize Socket Activity on the System keywords: network socket The socktop script periodically prints out a list of the processes with the highest socket activity. Command line options for the script allow filtering to focus on particular types of sockets. The "-h" option lists socktop script's filtering options. # ./socktop -c 1 network/stp_dump.stp - Dump of STP packets keywords: network traffic The stp_dump.stp prints out the packet contents. Each block contains the STP protocol ID, version ID, flags, root and bridge MAC addresses, and various times. # stap stp_dump.stp -T 5 network/tcp_connections.stp - Track Creation of Incoming TCP Connections keywords: network tcp socket The tcp_connections.stp script prints information for each new incoming TCP connection accepted by the computer. The information includes the UID, the command accepting the connection, the PID of the command, the port the connection is on, and the IP address of the originator of the request. # stap tcp_connections.stp -T 1 network/tcp_init_cwnd.stp - Increase Initial TCP Congestion Window to 10 keywords: network tcp socket guru Run the tcp_init_cwnd.stp script in the background to override a kernel's default tcp cwnd value to 10, which has been found to improve latency for web server type workloads. The script prints a count of cwnd value changes when it is stopped. # stap -g tcp_init_cwnd.stp -T 1 network/tcp_retransmission.stp - print tcp retransmission packet keywords: tcp retransmission The tcp_retransmission.stp prints out a line for each tcp retransmission packet # stap tcp_retransmission.stp -T 1 network/tcp_trace.stp - TCP Connection Tracing Utility keywords: network trace This scripts traces a given TCP connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port. # stap tcp_trace.stp 127.0.0.1:*-127.0.0.1:* timeout=1 network/tcpdumplike.stp - Dump of Received UDP/TCP Packets keywords: network traffic The tcpdumplike.stp prints out a line for each TCP & UDP packet received. Each line includes the source and destination IP addresses, the source and destination ports, and flags. # stap tcpdumplike.stp -T 1 network/tcpipstat.stp - Display Network Statistics for Individual TCP Sockets keywords: network statistics The tcpipstat script collects and displays network statistics related to individual TCP sockets or groups of sockets. The statistics that are collected are simular to that of the command netstat -s, only sorted and grouped by individual sockets. # stap tcpipstat.stp timeout=1 network/who_sent_it.stp - Trace threads sending network traffic to given host and/or port keywords: network trace traffic simple This script traces outgoing network packets using the netfilter probes (not requiring debuginfo), printing the source thread name/id and destination host:port. It may be filtered with the_dport and the_daddr globals, e.g., to watch only for DNS traffic (port 53), and/or only to the localhost (127.0.0.1). # stap who_sent_it.stp -G the_dport=53 -c "ping -c 1 sourceware.org || \ true" process/auditbt.stp - Generate backtraces for kernel audit events keywords: monitoring security backtrace Attaches to the kernel audit-log paths (also used by libaudit), and log every record being sent, along with a user-space backtrace of the process that caused it. # stap auditbt.stp -d /usr/bin/sudo --ldd -c "sudo true" process/chng_cpu.stp - Monitor Changes in Processor Executing a Task keywords: scheduler The chng_cpu.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name is found running on a different processor, the script prints out the thread id (tid), the executable name, the processor now running the task, the thread state, and a backtrace showing the kernel functions that triggered the running of the task on the processor. # stap chng_cpu.stp -T 1 bash process/cycle_thief.stp - Track IRQ's and Other Processes Stealing Cycles from a Task keywords: _best process scheduler time tracepoint interrupt The cycle_thief.stp script instruments the scheduler and IRQ handler to determine which processes and interrupts are competing with the specified task for the cpu cycles. This script uses the '-c' or '-x' options to focus on a specific task. The script output the number of times the task migrates between processors, histograms showing the length of time on and off processor, lists of processes running while the task is off the processor, and the interrupts that occurred while the task was running. # stap cycle_thief.stp -T 1 process/errsnoop.stp - Tabulate System Call Errors keywords: process syscall Prints a periodic tabular report about failing system calls, by process and by syscall failure. The first optional argument specifies the reporting interval (in seconds, default 5); the second optional argument gives a screen height (number of lines in the report, default 20). # stap errsnoop.stp 1 10 -T 1 process/forktracker.stp - Trace Creation of Processes keywords: process scheduler The forktracker.stp script prints out a time-stamped entry showing each fork and exec operation on the machine. This can be useful to determine what process is creating a flurry of short-lived processes. # stap forktracker.stp -T 1 process/futexes.stp - System-Wide Futex Contention keywords: syscall locking futex The script watches the futex syscall on the system. On exit the futex's address, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest. # stap futexes.stp -T 1 process/futexes2.stp - System-Wide Shared Futex Contention keywords: syscall locking futex The script watches just shared futex syscalls on the system. On exit the futex's key, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest. # stap futexes2.stp -T 1 process/ltrace.stp - uprobes-based ltrace keywords: process The ltrace.stp script lists calls that the designated process makes through PLTs (procedure linkage tables), generally into shared libraries. # stap ltrace.stp -c ls || echo PR14738 process/migrate.stp - Track the Migration of Specific Executables keywords: scheduler The migrate.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name migrates between processors an entry is printed with the process id (pid), the executable name, the processor off loading the task, and the process taking the task. Note that the task may or may not be executing at the time of the migration. # stap migrate.stp -T 1 bash process/mutex-contention.stp - pthread mutex contention analysis keywords: locking Tracks pthread-mutex initialization/use and underlying futex operations, to identify (with backtraces/symbol-names) the mutexes suffering most contention. Invoke with "-d SHLIB --ldd", perhaps with -DMAXMAPENTRIES=NNNN for some large NNNN, if the arrays overflow due to heavy activity. # stap mutex-contention.stp -T 1 process/noptrace.stp - Disable ptrace from Hierarchies of Processes keywords: process security guru Blocks ptrace(2) attempts from processes identified by stap -c/-x, as also specifiable from /proc/systemtap/stap_XXX/ control files. Processes may be added or removed from the blocked list. # stap -g noptrace.stp -c 'strace ls || true' process/pfiles.stp - Print Process File Descriptors keywords: process file Run pfiles.stp to produce a human-readable summary of all open file descriptors of a given process. Specify the process-id as -x PID for fastest performance. # stap -g pfiles.stp -x $$ process/plimit.stp - Print Resource Limits of Process keywords: process The script prints a variety of resource limits for a given pid, like /proc/$$/limits on recent kernels. # stap -g plimit.stp $$ process/procmod_watcher.stp - Monitor process creation/termination and module [un]loading keywords: process monitoring syscall tracepoint The procmod_watcher.stp script monitors calls to fork(), exec(), exit(), init_module(), and delete_module(). Event-specific details are also printed out (e.g. for exec(), the file being exec'ed). This script does not require debuginfo. # stap procmod_watcher.stp -T 1 process/proctop.stp - Periodically Print Process Information With History keywords: process scheduler _best Every 5 seconds, print out a list of 25 processes that took the most system time with information about the processes. Includes information on processes that may have exited while the script was running. The script contains configuration options listed in the script source. # stap proctop.stp -T 1 process/psig.stp - Print Process File Descriptors keywords: process signals Run psig.stp to produce a human-readable summary of the signal handling configuration of a given process. Specify the process-id as -x PID for fastest performance. # stap -DMAXACTION=10000 -g psig.stp -x $$ process/pstrace_exec.stp - Print trace of process ancestors for matching exec commands keywords: process backtrace The pstrace_exec.stp script watches each exec operation. If the exec contains a substring that matches the script's command-line argument, it prints out that process and all of its ancestors. # stap pstrace_exec.stp -T 1 bash process/pstree.stp - Generates a process diagram in DOT form. keywords: process diagram The pstree.stp script generates a process diagram in DOT form. For instance, it may be useful on a 'make' command to see all the processes that are started. # stap pstree.stp -T 1 process/rlimit_nofile.stp - Trace processes running out of file descriptors keywords: limits This script watches processes being scheduled and which try to allocate a file descriptor without luck. # stap rlimit_nofile.stp -T 1 process/sched-latency.stp - track wakeup-to-dispatch latency stats keywords: process scheduler time tracepoint This script periodically reports a histogram of the latency between a task (thread) being woken up and it actually being dispatched to a CPU: the amount of time it's spent in the runnable queue. # stap sched-latency.stp -T 7 process/schedtimes.stp - Track Time Processes Spend in Various States Using Tracepoints keywords: process scheduler time tracepoint The schedtimes.stp script instruments the scheduler to track the amount of time that each process spends in running, sleeping, queuing, and waiting for io. On exit the script prints out the accumulated time for each state of processes observed. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID and its children. # stap schedtimes.stp -T 1 process/semop-watch.stp - Watch semop(2)/semtimedop(2) operations keywords: process locking Prints a timed trace of semop(2)/semtimedop(2) syscalls # stap semop-watch.stp -c 'sleep 2' process/sig_by_pid.stp - Signal Counts by Process ID keywords: signals Print signal counts by process ID in descending order. # stap sig_by_pid.stp -T 1 process/sig_by_proc.stp - Signal Counts by Process Name keywords: signals Print signal counts by process name in descending order. # stap sig_by_proc.stp -T 1 process/sigkill.stp - Track SIGKILL Signals keywords: signals The script traces any SIGKILL signals. When that SIGKILL signal is sent to a process, the script prints out the signal name, the destination executable and process ID, the executable name and user ID that sents the signal. # stap sigkill.stp -T 1 process/sigmon.stp - Track a Particular Signal to a Specific Process keywords: signals The script watches for a particular signal sent to a specific process. When that signal is sent to the specified process, the script prints out the PID and executable of the process sending the signal, the PID and executable name of the process receiving the signal, and the signal number and name. # stap sigmon.stp -T 1 SIGKILL process/sleepingBeauties.stp - Generate Backtraces of Threads Waiting for IO Operations keywords: io scheduler backtrace The script monitors the time that threads spend in waiting for IO operations (in "D" state) in the wait_for_completion function. If a thread spends over 10ms, its name and backtrace is printed, and later so is the total delay. # stap sleepingBeauties.stp -T 1 process/sleeptime.stp - Trace Time Spent in Nanosleep Syscalls keywords: syscall nanosleep The script watches each nanosleep syscall on the system. At the end of each nanosleep syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "nanosleep:" key, and the duration of the sleep in microseconds. # stap sleeptime.stp -T 1 process/spawn_seeker.stp - Track Creation of Processes by process and execname keywords: process scheduler The spawn_seeker.stp script every minute (and on exit) prints out the local time and sorted lists of which processes and executables spawned tasks during the previous minute. This can be useful to determine what process is creating a flurry of short-lived processes. When a process exits its count of tasks created is added to its parent's count to better account for the indirect task creation by children processes. For more detailed examination of task creation consider using forktracker.stp. # stap spawn_seeker.stp -T 1 process/strace.stp - Trace system calls keywords: _best process syscall The script loosely emulates strace, when applied to individual processes or hierarchies (via -c/-x), or the entire system (without -c/-x). A few output configuration parameters may be set with -G. # stap strace.stp -c "cat /proc/sys/vm/* || true" process/syscalls_by_pid.stp - System-Wide Count of Syscalls by PID keywords: syscall The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each PID ordered from greatest to least number of syscalls. # stap syscalls_by_pid.stp -T 1 process/syscalls_by_proc.stp - System-Wide Count of Syscalls by Executable keywords: syscall The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each executable ordered from greatest to least number of syscalls. # stap syscalls_by_proc.stp -T 1 process/syscalltimes - System-Wide Syscall Statistics with Filtering keywords: syscall Combination shell/systemtap script to measure system call counts and times. Can be filtered by process IDs, process names and users. # ./syscalltimes -c 'sleep 1' process/thread-business.stp - monitor syscall history keywords: _best process syscall Prints a periodic tabular report about the counts of syscall activity of all threads on the system, along with a textual recent-syscall-history for each # stap thread-business.stp -T 10 process/threadstacks.stp - Override default new-pthread stack sizes keywords: thread guru Overrides default NPTL pthread_create stack size for all new threads created by target processes. Reports one line per process when the related glibc variable __default_stacksize is updated. Moot for glibc versions that support $LIBC_PTHREAD_DEFAULT_STACKSIZE_NP. # stap -g threadstacks.stp -Gsize=65536 -T 1 -d `which stap` process/wait4time.stp - Trace Time Spent in wait4 Syscalls keywords: syscall process The script watches each wait4 syscall on the system. At the end of each wait4 syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "wait4:" key, the duration of the wait and the PID that the wait4 was waiting for. If the waited for PID is not specified , it is "-1". # stap wait4time.stp -T 1 profiling/container_check.stp - Monitor capabilities and syscalls used by a process and it children keywords: profiling container syscall The container_check.stp script monitors the use of linux capablities and optionally forbidden syscalls by a process and its children. On exit the script prints out lists showing the capabilies used by each executable, which syscall used specific capabilites for each executable, a list of forbidden syscalls used, and details on any syscalls that failed during monitoring. This script is designed to help diagnose issues caused by restricted capabilies and syscalls when running an application in a container. If the script warns about skipped probes, the number of active kretprobes may need to be increased with "-DKRETACTIVE=100" option on the command line # stap container_check.stp -c "ping -c 1 sourceware.org || true" profiling/errno.stp - Show Which Processes and System Calls Return Errors Most Frequently keywords: profiling On exit the errno.stp script provides a sorted list showing which combination of PID, system call, and error occur most frequently. # stap errno.stp -T 1 profiling/fileline-profile.stp - Profile Kernel/User Functions keywords: profiling The fileline-profile.stp script ends by printing out a sorted list of the top twenty kernel and/or user processes providing file:line information, if available, from the samples addresses gathered over the time period the script is run. Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info. To include the symbol name in the output, specify guru mode (-g) and add symbolname="yes" to the stap command. # stap fileline-profile.stp -T 6 --all-modules --ldd profiling/fntimes.stp - Show Functions Taking Longer Than Usual keywords: _best profiling The fntimes.stp script monitors the execution time history of a given function family (assumed non-recursive). Each time (beyond a warmup interval) is then compared to the historical maximum. If it exceeds a certain threshold (250%), a message is printed. # stap fntimes.stp 'kernel.function("sys_*")' -T 7 profiling/functioncallcount.stp - Count Times Functions Are Called keywords: profiling function The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function. # stap -w functioncallcount.stp "*@mm/*.c" -T 1 profiling/ioctl_handler.stp - Monitor which executables use ioctl syscalls and what kernel code is handling the ioctl keywords: profiling The ioctl systemcall is used to manipulate devices setting or special files. The way that ioctl syscalls are handled depend greatly on the device the special file is associated with. Using strace to monitor the open and ioctl syscalls may not give a good indication of what kernel code is actually handling the ioctl operations. The ioctl_handler.stp script is designed to provide more details. On exit the ioctl_handler.stp script provides a count of the ioctl syscalls for each executable run on the system. If there was some special device driver code used to handle to the ioctl, the output will have a tally of the times the function name and module was called for that executable. The "--all-modules" option should be included on the command line so the script can provide function name information. # stap ioctl_handler.stp --all-modules -T 1 profiling/latencytap.stp - Show Reasons and Durations for Processes Sleeping keywords: _best profiling The latencytap.stp script collects data on the intervals processes are deactivated (sleeping). The script categorizes the reasons for the sleeps by analyzing the backtraces and displays a sorted list of the top 20 causes from largest total sum time sleeping to smallest. The output is updated every 30 seconds. The script needs to be compiled with the '--all-modules' option to produce reasons for sleeps caused by modules. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID. # stap latencytap.stp --all-modules -T 1 profiling/linetimes.stp - Show Time Spent on Each Line of a Function keywords: profiling _best The linetimes.stp script takes two arguments: where to find the function and the function name. linetimes.stp will instrument each line in the function. It will print out the number of times that the function is called, a table with the average and maximum time each line takes, and control flow information when the script exits. # stap linetimes.stp kernel do_nanosleep -T 1 profiling/perf.stp - Show performance ratios using perf.counter to access performance counters keywords: profiling On exit the perf.stp script provides a sorted list showing cycles per insn, branches per insn, and cache refs per insn # stap -w perf.stp -c "find /usr/bin -name \"l*\" -printf \"%h/%f %s %Cx \ %Ck%CM %Y\n\"" profiling/periodic.stp - Show the Period of the Various Timers on the System keywords: profiling The periodic.stp script uses the kernel.trace("timer_expire_entry") tracepoint to collect data on period and frequency of the various timers on the system. The script displays a sorted list of the timers observed on the system from most frequent to least frequent. The script needs to be compiled with the '--all-modules' option to produce list the function names. Optionally, this script can be used with a numerical argument to indicate the interval in seconds between printing output. # stap periodic.stp --all-modules -T 1 profiling/pf2.stp - Profile Kernel Functions keywords: profiling The pf2.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top ten kernel functions with samples. # stap pf2.stp -T 1 profiling/pf3.stp - Profile Kernel/User Functions keywords: profiling The pf3.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user functions with samples. Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info. # stap pf3.stp -T 6 --all-modules --ldd profiling/pf4.stp - Profile Kernel/User Backtraces keywords: _best profiling backtrace The pf4.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user stack backtraces (on a per-cpu basis). Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info. # stap pf4.stp -T 6 --all-modules --ldd profiling/sched_switch.stp - Display the Task Switches Happening in the Scheduler keywords: profiling function The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again. # stap sched_switch.stp -T 1 profiling/syscallerrorsbypid.stp - Provide a per-process syscall error tally on the system keywords: prometheus process syscall tracepoint The syscallerrorsbypid.stp script tallies syscall errors for each running process. This information can be useful to whether there are excessive errors for various processes on the system. The script makes the information available via procfs in Prometheus readable format. When a process exits its data will be eliminated from the prometheus output. To avoid exceeding the storage limitations of SystemTap older entries maybe overwritten by newer entries. This can lead to some active process syscall error counts disappearing and/or later reappearing with a lower value. Also note that the script does not properly name syscalls for 32-bit applications running on 64-bit machines. # stap syscallerrorsbypid.stp -T 1 profiling/syscalllatency.stp - Provide a per-process accumulation of syscall latency on the system keywords: prometheus process syscall tracepoint The syscalllatency.stp script accumulates syscall latency for each running process. This information can be useful to whether excessive time is being spent in particular syscalls on the system. The script makes the information available via procfs in Prometheus readable format. When a process exits its data will be eliminated from the prometheus output. To avoid exceeding the storage limitations of SystemTap older entries maybe overwritten by newer entries. This can lead to some active process syscall error counts disappearing and/or later reappearing with a lower value. Also note that the script does not properly name syscalls for 32-bit applications running on 64-bit machines. # stap syscalllatency.stp -T 1 profiling/syscallsbypid.stp - Provide a per-process syscall tally on the system keywords: prometheus process syscall tracepoint The syscallsbypid.stp script tallies each syscall for each running process. This information can be useful to determine the activity of various processes on the system. The script makes the information available via procfs in Prometheus readable format. When a process exits its data will be eliminated from the prometheus output. To avoid exceeding the storage limitations of SystemTap older entries maybe overwritten by newer entries. This can lead to some active process syscall counts disappearing and/or later reappearing with a lower value. Also note that the script does not properly name syscalls for 32-bit applications running on 64-bit machines. # stap syscallsbypid.stp -T 1 profiling/thread-times.stp - Profile Kernel Functions keywords: _best profiling The thread-times.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty threads occupying the CPUs, broken down as a percentage of user and kernel time. # stap thread-times.stp -T 1 profiling/timeout.stp - Show Processes Doing Polling Operations keywords: profiling The timeout.stp script is based on a blog entry (http://udrepper.livejournal.com/19041.html) mentioning a need for a tool to help developers find applications that are polling. The timeout.stp script monitors systemcall used for polling and records the systemcalls that timed out rather than returned because some action occurred. The script updates the screen once a second with the top twenty processes. # stap timeout.stp -T 1 profiling/topsys.stp - Show Processes Doing Polling Operations keywords: profiling The topsys.stp script lists out the top twenty systemcalls for the previous 5 seconds. The output is sorted from most frequent to least frequent. # stap topsys.stp -T 1 security-band-aids/cve-2008-0600.stp - cve-2008-0600 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2012-0056.stp - cve-2012-0056 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2013-2094.stp - cve-2013-2094 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2014-7169.stp - cve-2014-7169 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2015-0235.stp - cve-2015-0235 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2015-3456.stp - cve-2015-3456 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2015-7547.stp - cve-2015-7547 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2016-0728.stp - cve-2016-0728 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2016-5195.stp - cve-2016-5195 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2017-6074.stp - cve-2017-6074 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only security-band-aids/cve-2018-14634.stp - cve-2018-14634 security band-aid keywords: security guru historical emergency security band-aid, for reference/education only stapgames/2048.stp - 2048 keywords: _best stapgames The modern classic 2048 sliding-tiles game, using local keyboard and ansi animation. # stap -p4 2048.stp stapgames/block.stp - block breaker game keywords: stapgames A block game where you progressively break the ceiling blocks until clearing the level # stap -p4 -Itapset/ block.stp stapgames/eater.stp - eater game keywords: stapgames walk through a maze, eat stuff # stap -p4 -Itapset/ eater.stp stapgames/lifegame.stp - life game keywords: stapgames watch as your creation morphes into different forms # stap -p4 -Itapset/ lifegame.stp stapgames/pingpong.stp - pingpong game keywords: stapgames A simulated ball bounces around the terminal reflecting at the edges # stap -p4 -Itapset/ pingpong.stp virtualization/kvm_service_time.stp - Time Statistics on KVM Exit Reasons keywords: _best virtualization kvm The kvm_service_time.stp script tracks the statistics about the amount of time that the processor left the guest virtual machine for each exit reason (for example fixing up a page table or handling an IO operation). When the script exits it prints out the number of times each exit reason was encountered, the total duration of time it left the guest VM, the minimum time, the average time, and the maximum time in microseconds for that exit reason. On Linux 2.6.38 and newer kernel the script can automatically determine whether it is running on Intel or AMD processors. For older kernels with a kernel.trace("kvm_exit") tracepoint that does not have the $isa parameter you can explicitly state the kvm type with a "-G kvm=intel" or "-G kvm=amd" on the command line. # stap kvm_service_time.stp -T 1 virtualization/qemu_count.stp - Tally the Number of User-Space QEMU Events keywords: virtualization qemu kvm The qemu_count.stp script tallies the number of times each of the user-space qemu probepoints is encountered. When the script exits, it prints a list of the number of times each user-space qemu probepoint is encountered. # stap qemu_count.stp -T 1 virtualization/qemu_io.stp - Tally the Number of User-Space QEMU IO on Each IO Port keywords: virtualization qemu kvm io The qemu_io.stp script tallies the number of times each of the IO port on the guest virtual machines is touched by a input or output operation. When the script exits, it prints a count of the number of times each IO port read and written. # stap qemu_io.stp -T 1