| 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. |
| |
| Example usage: |
| perf sched record -- sleep 1 |
| perf sched latency |
| |
| ------------------------------------------------------------------------------------------------------------------------------------------- |
| Task | Runtime ms | Count | Avg delay ms | Max delay ms | Max delay start | Max delay end | |
| ------------------------------------------------------------------------------------------------------------------------------------------- |
| perf:(2) | 2.804 ms | 66 | avg: 0.524 ms | max: 1.069 ms | max start: 254752.314960 s | max end: 254752.316029 s |
| NetworkManager:1343 | 0.372 ms | 13 | avg: 0.008 ms | max: 0.013 ms | max start: 254751.551153 s | max end: 254751.551166 s |
| kworker/1:2-xfs:4649 | 0.012 ms | 1 | avg: 0.008 ms | max: 0.008 ms | max start: 254751.519807 s | max end: 254751.519815 s |
| kworker/3:1-xfs:388 | 0.011 ms | 1 | avg: 0.006 ms | max: 0.006 ms | max start: 254751.519809 s | max end: 254751.519815 s |
| sleep:147736 | 0.938 ms | 3 | avg: 0.006 ms | max: 0.007 ms | max start: 254751.313817 s | max end: 254751.313824 s |
| |
| It shows Runtime(time that a task spent actually running on the CPU), |
| Count(number of times a delay was calculated) and delay(time that a |
| task was ready to run but was kept waiting). |
| |
| Tasks with the same command name are merged and the merge count is |
| given within (), However if -p option is used, pid is mentioned. |
| |
| '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 runnable 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 latency' |
| ------------------------------- |
| |
| -C:: |
| --CPU <n>:: |
| CPU to profile on. |
| |
| -p:: |
| --pids:: |
| latency stats per pid instead of per command name. |
| |
| -s:: |
| --sort <key[,key2...]>:: |
| sort by key(s): runtime, switch, avg, max |
| by default it's sorted by "avg ,max ,switch ,runtime". |
| |
| 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. |
| |
| --task-name <task>:: |
| Map output only for the given task name(s). Separate the |
| task names with a comma (without whitespace). The sched-out |
| time is printed and is represented by '*-' for the given |
| task name(s). |
| ('-' indicates other tasks while '.' is idle). |
| |
| --fuzzy-name:: |
| Given task name(s) can be partially matched (fuzzy matching). |
| |
| 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. |
| |
| -C=:: |
| --cpu=:: |
| Only show events for the given CPU(s) (comma separated list). |
| |
| -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. |
| |
| OPTIONS for 'perf sched replay' |
| ------------------------------ |
| |
| -r:: |
| --repeat <n>:: |
| repeat the workload n times (0: infinite). Default is 10. |
| |
| SEE ALSO |
| -------- |
| linkperf:perf-record[1] |
