perf-sched.txt (4686B)
1perf-sched(1) 2============= 3 4NAME 5---- 6perf-sched - Tool to trace/measure scheduler properties (latencies) 7 8SYNOPSIS 9-------- 10[verse] 11'perf sched' {record|latency|map|replay|script|timehist} 12 13DESCRIPTION 14----------- 15There are several variants of 'perf sched': 16 17 'perf sched record <command>' to record the scheduling events 18 of an arbitrary workload. 19 20 'perf sched latency' to report the per task scheduling latencies 21 and other scheduling properties of the workload. 22 23 'perf sched script' to see a detailed trace of the workload that 24 was recorded (aliased to 'perf script' for now). 25 26 'perf sched replay' to simulate the workload that was recorded 27 via perf sched record. (this is done by starting up mockup threads 28 that mimic the workload based on the events in the trace. These 29 threads can then replay the timings (CPU runtime and sleep patterns) 30 of the workload as it occurred when it was recorded - and can repeat 31 it a number of times, measuring its performance.) 32 33 'perf sched map' to print a textual context-switching outline of 34 workload captured via perf sched record. Columns stand for 35 individual CPUs, and the two-letter shortcuts stand for tasks that 36 are running on a CPU. A '*' denotes the CPU that had the event, and 37 a dot signals an idle CPU. 38 39 'perf sched timehist' provides an analysis of scheduling events. 40 41 Example usage: 42 perf sched record -- sleep 1 43 perf sched timehist 44 45 By default it shows the individual schedule events, including the wait 46 time (time between sched-out and next sched-in events for the task), the 47 task scheduling delay (time between wakeup and actually running) and run 48 time for the task: 49 50 time cpu task name wait time sch delay run time 51 [tid/pid] (msec) (msec) (msec) 52 -------------- ------ -------------------- --------- --------- --------- 53 79371.874569 [0011] gcc[31949] 0.014 0.000 1.148 54 79371.874591 [0010] gcc[31951] 0.000 0.000 0.024 55 79371.874603 [0010] migration/10[59] 3.350 0.004 0.011 56 79371.874604 [0011] <idle> 1.148 0.000 0.035 57 79371.874723 [0005] <idle> 0.016 0.000 1.383 58 79371.874746 [0005] gcc[31949] 0.153 0.078 0.022 59 ... 60 61 Times are in msec.usec. 62 63OPTIONS 64------- 65-i:: 66--input=<file>:: 67 Input file name. (default: perf.data unless stdin is a fifo) 68 69-v:: 70--verbose:: 71 Be more verbose. (show symbol address, etc) 72 73-D:: 74--dump-raw-trace=:: 75 Display verbose dump of the sched data. 76 77-f:: 78--force:: 79 Don't complain, do it. 80 81OPTIONS for 'perf sched map' 82---------------------------- 83 84--compact:: 85 Show only CPUs with activity. Helps visualizing on high core 86 count systems. 87 88--cpus:: 89 Show just entries with activities for the given CPUs. 90 91--color-cpus:: 92 Highlight the given cpus. 93 94--color-pids:: 95 Highlight the given pids. 96 97OPTIONS for 'perf sched timehist' 98--------------------------------- 99-k:: 100--vmlinux=<file>:: 101 vmlinux pathname 102 103--kallsyms=<file>:: 104 kallsyms pathname 105 106-g:: 107--call-graph:: 108 Display call chains if present (default on). 109 110--max-stack:: 111 Maximum number of functions to display in backtrace, default 5. 112 113-C=:: 114--cpu=:: 115 Only show events for the given CPU(s) (comma separated list). 116 117-p=:: 118--pid=:: 119 Only show events for given process ID (comma separated list). 120 121-t=:: 122--tid=:: 123 Only show events for given thread ID (comma separated list). 124 125-s:: 126--summary:: 127 Show only a summary of scheduling by thread with min, max, and average 128 run times (in sec) and relative stddev. 129 130-S:: 131--with-summary:: 132 Show all scheduling events followed by a summary by thread with min, 133 max, and average run times (in sec) and relative stddev. 134 135--symfs=<directory>:: 136 Look for files with symbols relative to this directory. 137 138-V:: 139--cpu-visual:: 140 Show visual aid for sched switches by CPU: 'i' marks idle time, 141 's' are scheduler events. 142 143-w:: 144--wakeups:: 145 Show wakeup events. 146 147-M:: 148--migrations:: 149 Show migration events. 150 151-n:: 152--next:: 153 Show next task. 154 155-I:: 156--idle-hist:: 157 Show idle-related events only. 158 159--time:: 160 Only analyze samples within given time window: <start>,<stop>. Times 161 have the format seconds.microseconds. If start is not given (i.e., time 162 string is ',x.y') then analysis starts at the beginning of the file. If 163 stop time is not given (i.e, time string is 'x.y,') then analysis goes 164 to end of file. 165 166--state:: 167 Show task state when it switched out. 168 169SEE ALSO 170-------- 171linkperf:perf-record[1]