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| -rw-r--r-- | tools/perf/Documentation/perf-sched.txt | 167 |
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diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt new file mode 100644 index 000000000..63f938b88 --- /dev/null +++ b/tools/perf/Documentation/perf-sched.txt @@ -0,0 +1,167 @@ +perf-sched(1) +============= + +NAME +---- +perf-sched - Tool to trace/measure scheduler properties (latencies) + +SYNOPSIS +-------- +[verse] +'perf sched' {record|latency|map|replay|script|timehist} + +DESCRIPTION +----------- +There are several variants of 'perf sched': + + 'perf sched record <command>' to record the scheduling events + of an arbitrary workload. + + 'perf sched latency' to report the per task scheduling latencies + and other scheduling properties of the workload. + + 'perf sched script' to see a detailed trace of the workload that + was recorded (aliased to 'perf script' for now). + + 'perf sched replay' to simulate the workload that was recorded + via perf sched record. (this is done by starting up mockup threads + that mimic the workload based on the events in the trace. These + threads can then replay the timings (CPU runtime and sleep patterns) + of the workload as it occurred when it was recorded - and can repeat + it a number of times, measuring its performance.) + + 'perf sched map' to print a textual context-switching outline of + workload captured via perf sched record. Columns stand for + individual CPUs, and the two-letter shortcuts stand for tasks that + are running on a CPU. A '*' denotes the CPU that had the event, and + a dot signals an idle CPU. + + 'perf sched timehist' provides an analysis of scheduling events. + + Example usage: + perf sched record -- sleep 1 + perf sched timehist + + By default it shows the individual schedule events, including the wait + time (time between sched-out and next sched-in events for the task), the + task scheduling delay (time between wakeup and actually running) and run + time for the task: + + time cpu task name wait time sch delay run time + [tid/pid] (msec) (msec) (msec) + -------------- ------ -------------------- --------- --------- --------- + 79371.874569 [0011] gcc[31949] 0.014 0.000 1.148 + 79371.874591 [0010] gcc[31951] 0.000 0.000 0.024 + 79371.874603 [0010] migration/10[59] 3.350 0.004 0.011 + 79371.874604 [0011] <idle> 1.148 0.000 0.035 + 79371.874723 [0005] <idle> 0.016 0.000 1.383 + 79371.874746 [0005] gcc[31949] 0.153 0.078 0.022 + ... + + Times are in msec.usec. + +OPTIONS +------- +-i:: +--input=<file>:: + Input file name. (default: perf.data unless stdin is a fifo) + +-v:: +--verbose:: + Be more verbose. (show symbol address, etc) + +-D:: +--dump-raw-trace=:: + Display verbose dump of the sched data. + +-f:: +--force:: + Don't complain, do it. + +OPTIONS for 'perf sched map' +---------------------------- + +--compact:: + Show only CPUs with activity. Helps visualizing on high core + count systems. + +--cpus:: + Show just entries with activities for the given CPUs. + +--color-cpus:: + Highlight the given cpus. + +--color-pids:: + Highlight the given pids. + +OPTIONS for 'perf sched timehist' +--------------------------------- +-k:: +--vmlinux=<file>:: + vmlinux pathname + +--kallsyms=<file>:: + kallsyms pathname + +-g:: +--call-graph:: + Display call chains if present (default on). + +--max-stack:: + Maximum number of functions to display in backtrace, default 5. + +-p=:: +--pid=:: + Only show events for given process ID (comma separated list). + +-t=:: +--tid=:: + Only show events for given thread ID (comma separated list). + +-s:: +--summary:: + Show only a summary of scheduling by thread with min, max, and average + run times (in sec) and relative stddev. + +-S:: +--with-summary:: + Show all scheduling events followed by a summary by thread with min, + max, and average run times (in sec) and relative stddev. + +--symfs=<directory>:: + Look for files with symbols relative to this directory. + +-V:: +--cpu-visual:: + Show visual aid for sched switches by CPU: 'i' marks idle time, + 's' are scheduler events. + +-w:: +--wakeups:: + Show wakeup events. + +-M:: +--migrations:: + Show migration events. + +-n:: +--next:: + Show next task. + +-I:: +--idle-hist:: + Show idle-related events only. + +--time:: + Only analyze samples within given time window: <start>,<stop>. Times + have the format seconds.microseconds. If start is not given (i.e., time + string is ',x.y') then analysis starts at the beginning of the file. If + stop time is not given (i.e, time string is 'x.y,') then analysis goes + to end of file. + +--state:: + Show task state when it switched out. + +SEE ALSO +-------- +linkperf:perf-record[1] |