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 Example usage: 24 perf sched record -- sleep 1 25 perf sched latency 26 27 ------------------------------------------------------------------------------------------------------------------------------------------- 28 Task | Runtime ms | Count | Avg delay ms | Max delay ms | Max delay start | Max delay end | 29 ------------------------------------------------------------------------------------------------------------------------------------------- 30 perf:(2) | 2.804 ms | 66 | avg: 0.524 ms | max: 1.069 ms | max start: 254752.314960 s | max end: 254752.316029 s 31 NetworkManager:1343 | 0.372 ms | 13 | avg: 0.008 ms | max: 0.013 ms | max start: 254751.551153 s | max end: 254751.551166 s 32 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 33 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 34 sleep:147736 | 0.938 ms | 3 | avg: 0.006 ms | max: 0.007 ms | max start: 254751.313817 s | max end: 254751.313824 s 35 36 It shows Runtime(time that a task spent actually running on the CPU), 37 Count(number of times a delay was calculated) and delay(time that a 38 task was ready to run but was kept waiting). 39 40 Tasks with the same command name are merged and the merge count is 41 given within (), However if -p option is used, pid is mentioned. 42 43 'perf sched script' to see a detailed trace of the workload that 44 was recorded (aliased to 'perf script' for now). 45 46 'perf sched replay' to simulate the workload that was recorded 47 via perf sched record. (this is done by starting up mockup threads 48 that mimic the workload based on the events in the trace. These 49 threads can then replay the timings (CPU runtime and sleep patterns) 50 of the workload as it occurred when it was recorded - and can repeat 51 it a number of times, measuring its performance.) 52 53 'perf sched map' to print a textual context-switching outline of 54 workload captured via perf sched record. Columns stand for 55 individual CPUs, and the two-letter shortcuts stand for tasks that 56 are running on a CPU. A '*' denotes the CPU that had the event, and 57 a dot signals an idle CPU. 58 59 'perf sched timehist' provides an analysis of scheduling events. 60 61 Example usage: 62 perf sched record -- sleep 1 63 perf sched timehist 64 65 By default it shows the individual schedule events, including the wait 66 time (time between sched-out and next sched-in events for the task), the 67 task scheduling delay (time between runnable and actually running) and 68 run time for the task: 69 70 time cpu task name wait time sch delay run time 71 [tid/pid] (msec) (msec) (msec) 72 -------------- ------ -------------------- --------- --------- --------- 73 79371.874569 [0011] gcc[31949] 0.014 0.000 1.148 74 79371.874591 [0010] gcc[31951] 0.000 0.000 0.024 75 79371.874603 [0010] migration/10[59] 3.350 0.004 0.011 76 79371.874604 [0011] <idle> 1.148 0.000 0.035 77 79371.874723 [0005] <idle> 0.016 0.000 1.383 78 79371.874746 [0005] gcc[31949] 0.153 0.078 0.022 79 ... 80 81 Times are in msec.usec. 82 83OPTIONS 84------- 85-i:: 86--input=<file>:: 87 Input file name. (default: perf.data unless stdin is a fifo) 88 89-v:: 90--verbose:: 91 Be more verbose. (show symbol address, etc) 92 93-D:: 94--dump-raw-trace=:: 95 Display verbose dump of the sched data. 96 97-f:: 98--force:: 99 Don't complain, do it. 100 101OPTIONS for 'perf sched latency' 102------------------------------- 103 104-C:: 105--CPU <n>:: 106 CPU to profile on. 107 108-p:: 109--pids:: 110 latency stats per pid instead of per command name. 111 112-s:: 113--sort <key[,key2...]>:: 114 sort by key(s): runtime, switch, avg, max 115 by default it's sorted by "avg ,max ,switch ,runtime". 116 117OPTIONS for 'perf sched map' 118---------------------------- 119 120--compact:: 121 Show only CPUs with activity. Helps visualizing on high core 122 count systems. 123 124--cpus:: 125 Show just entries with activities for the given CPUs. 126 127--color-cpus:: 128 Highlight the given cpus. 129 130--color-pids:: 131 Highlight the given pids. 132 133--task-name <task>:: 134 Map output only for the given task name(s). Separate the 135 task names with a comma (without whitespace). The sched-out 136 time is printed and is represented by '*-' for the given 137 task name(s). 138 ('-' indicates other tasks while '.' is idle). 139 140--fuzzy-name:: 141 Given task name(s) can be partially matched (fuzzy matching). 142 143OPTIONS for 'perf sched timehist' 144--------------------------------- 145-k:: 146--vmlinux=<file>:: 147 vmlinux pathname 148 149--kallsyms=<file>:: 150 kallsyms pathname 151 152-g:: 153--call-graph:: 154 Display call chains if present (default on). 155 156--max-stack:: 157 Maximum number of functions to display in backtrace, default 5. 158 159-C=:: 160--cpu=:: 161 Only show events for the given CPU(s) (comma separated list). 162 163-p=:: 164--pid=:: 165 Only show events for given process ID (comma separated list). 166 167-t=:: 168--tid=:: 169 Only show events for given thread ID (comma separated list). 170 171-s:: 172--summary:: 173 Show only a summary of scheduling by thread with min, max, and average 174 run times (in sec) and relative stddev. 175 176-S:: 177--with-summary:: 178 Show all scheduling events followed by a summary by thread with min, 179 max, and average run times (in sec) and relative stddev. 180 181--symfs=<directory>:: 182 Look for files with symbols relative to this directory. 183 184-V:: 185--cpu-visual:: 186 Show visual aid for sched switches by CPU: 'i' marks idle time, 187 's' are scheduler events. 188 189-w:: 190--wakeups:: 191 Show wakeup events. 192 193-M:: 194--migrations:: 195 Show migration events. 196 197-n:: 198--next:: 199 Show next task. 200 201-I:: 202--idle-hist:: 203 Show idle-related events only. 204 205--time:: 206 Only analyze samples within given time window: <start>,<stop>. Times 207 have the format seconds.microseconds. If start is not given (i.e., time 208 string is ',x.y') then analysis starts at the beginning of the file. If 209 stop time is not given (i.e, time string is 'x.y,') then analysis goes 210 to end of file. 211 212--state:: 213 Show task state when it switched out. 214 215--show-prio:: 216 Show task priority. 217 218--prio:: 219 Only show events for given task priority(ies). Multiple priorities can be 220 provided as a comma-separated list with no spaces: 0,120. Ranges of 221 priorities are specified with -: 120-129. A combination of both can also be 222 provided: 0,120-129. 223 224OPTIONS for 'perf sched replay' 225------------------------------ 226 227-r:: 228--repeat <n>:: 229 repeat the workload n times (0: infinite). Default is 10. 230 231SEE ALSO 232-------- 233linkperf:perf-record[1] 234