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| -rw-r--r-- | tools/perf/Documentation/perf-ftrace.txt | 75 |
1 files changed, 52 insertions, 23 deletions
diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt index 6e82b7cc0bf0..df4595563801 100644 --- a/tools/perf/Documentation/perf-ftrace.txt +++ b/tools/perf/Documentation/perf-ftrace.txt @@ -9,32 +9,24 @@ perf-ftrace - simple wrapper for kernel's ftrace functionality SYNOPSIS -------- [verse] -'perf ftrace' <command> +'perf ftrace' {trace|latency} <command> DESCRIPTION ----------- -The 'perf ftrace' command is a simple wrapper of kernel's ftrace -functionality. It only supports single thread tracing currently and -just reads trace_pipe in text and then write it to stdout. +The 'perf ftrace' command provides a collection of subcommands which use +kernel's ftrace infrastructure. -The following options apply to perf ftrace. + '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. -OPTIONS -------- + 'perf ftrace latency' calculates execution latency of a given function + (optionally with BPF) and display it as a histogram. --t:: ---tracer=:: - Tracer to use when neither -G nor -F option is not - specified: function_graph or function. +The following options apply to perf ftrace. --v:: ---verbose:: - Increase the verbosity level. - --F:: ---funcs:: - List available functions to trace. It accepts a pattern to - only list interested functions. +COMMON OPTIONS +-------------- -p:: --pid=:: @@ -43,10 +35,6 @@ OPTIONS --tid=:: Trace on existing thread id (comma separated list). --D:: ---delay:: - Time (ms) to wait before starting tracing after program start. - -a:: --all-cpus:: Force system-wide collection. Scripts run without a <command> @@ -61,6 +49,28 @@ OPTIONS Ranges of CPUs are specified with -: 0-2. Default is to trace on all online CPUs. +-v:: +--verbose:: + Increase the verbosity level. + + +OPTIONS for 'perf ftrace trace' +------------------------------- + +-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 @@ -114,6 +124,25 @@ OPTIONS thresh=<n> - Setup trace duration threshold in microseconds. depth=<n> - Set max depth for function graph tracer to follow. + +OPTIONS for 'perf ftrace latency' +--------------------------------- + +-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. + + SEE ALSO -------- linkperf:perf-record[1], linkperf:perf-trace[1] |