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Diffstat (limited to 'tools/perf/Documentation/perf-ftrace.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-ftrace.txt | 131 |
1 files changed, 97 insertions, 34 deletions
diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt index b80c84307dc9..d780b93fcf87 100644 --- a/tools/perf/Documentation/perf-ftrace.txt +++ b/tools/perf/Documentation/perf-ftrace.txt @@ -9,31 +9,32 @@ 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: function_graph or function. +The following options apply to perf ftrace. --v:: ---verbose=:: - Verbosity level. +COMMON OPTIONS +-------------- -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> @@ -48,39 +49,101 @@ 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 + be a number with appended unit character - B/K/M/G. + +--inherit:: + Trace children processes spawned by our target. + -T:: --trace-funcs=:: - Only trace functions given by the argument. 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. + 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=:: - 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. + 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=:: - Set graph filter on the given function (or a glob pattern). - This is useful for the function_graph tracer only and enables - tracing 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. + 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=:: - 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. + 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. + + +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. --D:: ---graph-depth=:: - Set max depth for function graph tracer to follow SEE ALSO -------- |