perf-ftrace(1) — Linux manual page


PERF-FTRACE(1)                 perf Manual                PERF-FTRACE(1)

NAME         top

       perf-ftrace - simple wrapper for kernel's ftrace functionality

SYNOPSIS         top

       perf ftrace {trace|latency} <command>

DESCRIPTION         top

       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.

COMMON OPTIONS         top

       -p, --pid=
           Trace on existing process id (comma separated list).

           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

       -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.

           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.

           List of options allowed to set:

           •   call-graph - Display kernel stack trace for function

           •   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.

           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

           •   depth=<n> - Set max depth for function graph tracer to


       -T, --trace-funcs=
           Set the function name to get the histogram. Unlike perf
           ftrace trace, it only allows single function to calculate the

       -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

SEE ALSO         top

       perf-record(1), perf-trace(1)

COLOPHON         top

       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 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       on 2023-12-22.  (At that time, the date of the most recent commit
       that was found in the repository was 2023-12-21.)  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

perf                           2023-08-16                 PERF-FTRACE(1)

Pages that refer to this page: perf(1)