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NAME | SYNOPSIS | DESCRIPTION | COMMON OPTIONS | OPTIONS FOR PERF FTRACE TRACE | OPTIONS FOR PERF FTRACE LATENCY | SEE ALSO | COLOPHON |
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PERF-FTRACE(1) perf Manual PERF-FTRACE(1)
perf-ftrace - simple wrapper for kernel's ftrace functionality
perf ftrace {trace|latency} <command>
The perf ftrace command provides a collection of subcommands
which use kernel’s ftrace infrastructure.
'perf ftrace trace' is a simple wrapper of the ftrace. It only supports
single thread tracing currently and just reads trace_pipe in text and then
write it to stdout.
'perf ftrace latency' calculates execution latency of a given function
(optionally with BPF) and display it as a histogram.
The following options apply to perf ftrace.
-p, --pid=
Trace on existing process id (comma separated list).
--tid=
Trace on existing thread id (comma separated list).
-a, --all-cpus
Force system-wide collection. Scripts run without a <command>
normally use -a by default, while scripts run with a
<command> normally don’t - this option allows the latter to
be run in system-wide mode.
-C, --cpu=
Only trace for the list of CPUs provided. Multiple CPUs can
be provided as a comma separated list with no space like:
0,1. Ranges of CPUs are specified with -: 0-2. Default is to
trace on all online CPUs.
-v, --verbose
Increase the verbosity level.
-t, --tracer=
Tracer to use when neither -G nor -F option is not specified:
function_graph or function.
-F, --funcs
List available functions to trace. It accepts a pattern to
only list interested functions.
-D, --delay
Time (ms) to wait before starting tracing after program
start.
-m, --buffer-size
Set the size of per-cpu tracing buffer, <size> is expected to
be a number with appended unit character - B/K/M/G.
--inherit
Trace children processes spawned by our target.
-T, --trace-funcs=
Select function tracer and set function filter on the given
function (or a glob pattern). Multiple functions can be given
by using this option more than once. The function argument
also can be a glob pattern. It will be passed to
set_ftrace_filter in tracefs.
-N, --notrace-funcs=
Select function tracer and do not trace functions given by
the argument. Like -T option, this can be used more than once
to specify multiple functions (or glob patterns). It will be
passed to set_ftrace_notrace in tracefs.
--func-opts
List of options allowed to set:
• call-graph - Display kernel stack trace for function
tracer.
• irq-info - Display irq context info for function tracer.
-G, --graph-funcs=
Select function_graph tracer and set graph filter on the
given function (or a glob pattern). This is useful to trace
for functions executed from the given function. This can be
used more than once to specify multiple functions. It will be
passed to set_graph_function in tracefs.
-g, --nograph-funcs=
Select function_graph tracer and set graph notrace filter on
the given function (or a glob pattern). Like -G option, this
is useful for the function_graph tracer only and disables
tracing for function executed from the given function. This
can be used more than once to specify multiple functions. It
will be passed to set_graph_notrace in tracefs.
--graph-opts
List of options allowed to set:
• nosleep-time - Measure on-CPU time only for
function_graph tracer.
• noirqs - Ignore functions that happen inside interrupt.
• verbose - Show process names, PIDs, timestamps, etc.
• thresh=<n> - Setup trace duration threshold in
microseconds.
• depth=<n> - Set max depth for function graph tracer to
follow.
-T, --trace-funcs=
Set the function name to get the histogram. Unlike perf
ftrace trace, it only allows single function to calculate the
histogram.
-b, --use-bpf
Use BPF to measure function latency instead of using the
ftrace (it uses function_graph tracer internally).
-n, --use-nsec
Use nano-second instead of micro-second as a base unit of the
histogram.
perf-record(1), perf-trace(1)
This page is part of the perf (Performance analysis tools for
Linux (in Linux source tree)) project. Information about the
project can be found at
⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩. If you have a
bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩
on 2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-06-13.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
perf 2023-08-16 PERF-FTRACE(1)
Pages that refer to this page: perf(1)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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