Multiple cgroups: perf trace -G A -e sched:*switch -G B the syscall ones go to the 'A' cgroup, the sched:sched_switch goes to the 'B' cgroup. --filter-pids= Filter out events for these pids and for trace itself (comma separated list). -v, --verbose Increase the verbosity level.

These example sequences have been chosen to illustrate some different ways that perf is used, from gathering to reporting. Performance counter summaries, including IPC, for the gzip command: ... Dynamically instrument the kernel tcp_sendmsg() function, and trace it for 5 seconds, with stack traces:

Trace the next two sched:sched_switch events, four block:*_plug events, the next block:*_unplug and the next three net:*dev_queue events, this last one with a backtrace of at most 16 entries, system wide: # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/ 0.000 :0/0 sched:sched_switch:swapper/2:0 [120] S ==> rcu_sched:10 [120] 0.015 rcu_sched/10 sched:sched_switch:rcu_sched:10 [120] R ==> swapper/2:0 [120] 254.198 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=66 __dev_queue_xmit ([kernel.kallsyms]) 273.

December 18, 2018 - # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/

Trace only major pagefaults: $ perf trace --no-syscalls -F Trace syscalls, major and minor pagefaults: $ perf trace -F all 1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.) As you can see, there was major pagefault in ...

When tracing pagefaults, the format of the trace is as follows: <min|maj>fault [<ip.symbol>+<ip.offset>] ⇒ <m[blue]addr.dso [at] addr.offsetm[] ... • ip.symbol shows symbol for instruction pointer (the code that generated the fault); if ...

By right-clicking the trace and selecting Configure symbols menu item, the symbol files can be added, ie the kallsyms file and any other file containing symbol mapping. For example, if tracing a java application with the perf-map-agent project, the .map file contains symbols that can be resolved.

This produces a perf-data-<dat... perf_trace_viewer script. This requires Python 3.10 or later. For example, ./perf_trace_viewer <input file> <output file>....

July 4, 2022 - Short tutorial about perf trace, an strace-inspired system troubleshooting functionality in the Linux perf toolbox, including basic usage, flags and options, some examples, and more

Here's a simple example of Linux perf_events static tracepoints: tracing disk I/O.

For example: $ perf record –a –e 'sched:sched_switch' sleep 3 $ perf script –g Python generated Python script: perf-script.py $ perf script -s ./perf-script.py in trace_begin sched__sched_switch 3 664597.912692243 21223 perf prev_comm=perf^@-terminal-^@, prev_pid=21223, prev_prio=120, prev_state=, next_comm=migration/3^@^@^@^@^@, next_pid=23, next_prio=0 […]

GitLab CI/CD is a tool used for automating the process of testing, building, and deploying code. It helps developers integrate and deliver software quickly and reliably. Here’s a breakdown of the p · © 2025 Sandeep. Some rights reserved

Trace the next two sched:sched_switch events, four block:*_plug events, the next block:*_unplug and the next three net:*dev_queue events, this last one with a backtrace of at most 16 entries, system wide: # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/ 0.000 :0/0 sched:sched_switch:swapper/2:0 [120] S ==> rcu_sched:10 [120] 0.015 rcu_sched/10 sched:sched_switch:rcu_sched:10 [120] R ==> swapper/2:0 [120] 254.198 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=66 __dev_queue_xmit ([kernel.kallsyms]) 273.

To create a perf session with AUX pause / resume, three configuration terms are introduced: “aux-action=start-paused”: it is specified for the cs_etm PMU event to launch in a paused state. “aux-action=pause”: an associated event is specified with this term to pause AUX trace. “aux-action=resume”: an associated event is specified with this term to resume AUX trace. Example for triggering AUX pause and resume with ftrace tracepoints:

'perf ftrace latency' calculates execution latency of a given function (optionally with BPF) and display it as a histogram. 'perf ftrace profile' show a execution profile for each function including total, average, max time and the number of calls. The following options apply to perf ftrace. -p, --pid= Trace on existing process id (comma separated list).

The majority of packet processing is performed on core 0, only a fraction of outgoing packets are processed on core 1 (middle display). The function display on the right side again reflects the majority of CPU time being spent on PHP processing ...

Apr 2021 What problems do people solve with strace? Dec 2017 A perf cheat sheet Jul 2017 Linux tracing systems & how they fit together Jun 2017 Notes on BPF & eBPF Jun 2017 3 short screencasts (/proc, tcpdump, strace) Mar 2017 ftrace: trace your kernel functions!

November 13, 2013 - Tracing with Perf tools · 2013-11-13 Wed · 22 / 34 · Other technologies · systemtap · use custom script language (tapset) supports kernel and user level tracing · using kprobes and uprobes · compile kernel module and load at runtime · convert script to C source file · compile it with system compiler (gcc) SDT defines user-level tracepoints ...

perf probe [options] --add=PROBE [...] or perf probe [options] PROBE or perf probe [options] --del=[GROUP:]EVENT [...] or perf probe --list or perf probe [options] --line=LINE or perf probe [options] --vars=PROBEPOINT · This command defines dynamic tracepoint events, by symbol and registers without debuginfo, or by C expressions (C line numbers, C function names, and C local variables) with debuginfo.