149 lines
4.1 KiB
Plaintext
149 lines
4.1 KiB
Plaintext
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perf-ftrace(1)
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==============
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NAME
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----
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perf-ftrace - simple wrapper for kernel's ftrace functionality
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SYNOPSIS
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--------
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[verse]
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'perf ftrace' {trace|latency} <command>
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DESCRIPTION
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-----------
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The 'perf ftrace' command provides a collection of subcommands which use
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kernel's ftrace infrastructure.
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'perf ftrace trace' is a simple wrapper of the ftrace. It only supports
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single thread tracing currently and just reads trace_pipe in text and then
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write it to stdout.
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'perf ftrace latency' calculates execution latency of a given function
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(optionally with BPF) and display it as a histogram.
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The following options apply to perf ftrace.
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COMMON OPTIONS
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--------------
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-p::
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--pid=::
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Trace on existing process id (comma separated list).
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--tid=::
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Trace on existing thread id (comma separated list).
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-a::
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--all-cpus::
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Force system-wide collection. Scripts run without a <command>
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normally use -a by default, while scripts run with a <command>
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normally don't - this option allows the latter to be run in
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system-wide mode.
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-C::
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--cpu=::
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Only trace for the list of CPUs provided. Multiple CPUs can
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be provided as a comma separated list with no space like: 0,1.
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Ranges of CPUs are specified with -: 0-2.
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Default is to trace on all online CPUs.
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-v::
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--verbose::
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Increase the verbosity level.
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OPTIONS for 'perf ftrace trace'
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-------------------------------
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-t::
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--tracer=::
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Tracer to use when neither -G nor -F option is not
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specified: function_graph or function.
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-F::
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--funcs::
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List available functions to trace. It accepts a pattern to
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only list interested functions.
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-D::
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--delay::
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Time (ms) to wait before starting tracing after program start.
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-m::
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--buffer-size::
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Set the size of per-cpu tracing buffer, <size> is expected to
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be a number with appended unit character - B/K/M/G.
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--inherit::
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Trace children processes spawned by our target.
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-T::
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--trace-funcs=::
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Select function tracer and set function filter on the given
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function (or a glob pattern). Multiple functions can be given
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by using this option more than once. The function argument also
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can be a glob pattern. It will be passed to 'set_ftrace_filter'
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in tracefs.
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-N::
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--notrace-funcs=::
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Select function tracer and do not trace functions given by the
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argument. Like -T option, this can be used more than once to
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specify multiple functions (or glob patterns). It will be
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passed to 'set_ftrace_notrace' in tracefs.
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--func-opts::
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List of options allowed to set:
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call-graph - Display kernel stack trace for function tracer.
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irq-info - Display irq context info for function tracer.
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-G::
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--graph-funcs=::
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Select function_graph tracer and set graph filter on the given
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function (or a glob pattern). This is useful to trace for
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functions executed from the given function. This can be used more
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than once to specify multiple functions. It will be passed to
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'set_graph_function' in tracefs.
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-g::
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--nograph-funcs=::
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Select function_graph tracer and set graph notrace filter on the
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given function (or a glob pattern). Like -G option, this is useful
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for the function_graph tracer only and disables tracing for function
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executed from the given function. This can be used more than once to
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specify multiple functions. It will be passed to 'set_graph_notrace'
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in tracefs.
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--graph-opts::
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List of options allowed to set:
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nosleep-time - Measure on-CPU time only for function_graph tracer.
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noirqs - Ignore functions that happen inside interrupt.
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verbose - Show process names, PIDs, timestamps, etc.
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thresh=<n> - Setup trace duration threshold in microseconds.
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depth=<n> - Set max depth for function graph tracer to follow.
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OPTIONS for 'perf ftrace latency'
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---------------------------------
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-T::
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--trace-funcs=::
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Set the function name to get the histogram. Unlike perf ftrace trace,
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it only allows single function to calculate the histogram.
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-b::
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--use-bpf::
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Use BPF to measure function latency instead of using the ftrace (it
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uses function_graph tracer internally).
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-n::
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--use-nsec::
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Use nano-second instead of micro-second as a base unit of the histogram.
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SEE ALSO
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--------
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linkperf:perf-record[1], linkperf:perf-trace[1]
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