1PERF-SCHED(1) perf Manual PERF-SCHED(1)
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6 perf-sched - Tool to trace/measure scheduler properties (latencies)
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9 perf sched {record|latency|map|replay|script|timehist}
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12 There are several variants of perf sched:
13 'perf sched record <command>' to record the scheduling events
15 of an arbitrary workload.
16 'perf sched latency' to report the per task scheduling latencies
18 and other scheduling properties of the workload.
19 'perf sched script' to see a detailed trace of the workload that
21 was recorded (aliased to 'perf script' for now).
22 'perf sched replay' to simulate the workload that was recorded
24 via perf sched record. (this is done by starting up mockup threads
25 that mimic the workload based on the events in the trace. These
26 threads can then replay the timings (CPU runtime and sleep patterns)
27 of the workload as it occurred when it was recorded - and can repeat
28 it a number of times, measuring its performance.)
29 'perf sched map' to print a textual context-switching outline of
31 workload captured via perf sched record. Columns stand for
32 individual CPUs, and the two-letter shortcuts stand for tasks that
33 are running on a CPU. A '*' denotes the CPU that had the event, and
34 a dot signals an idle CPU.
35 'perf sched timehist' provides an analysis of scheduling events.
37 Example usage:
39 perf sched record -- sleep 1
40 perf sched timehist
41 By default it shows the individual schedule events, including the wait
43 time (time between sched-out and next sched-in events for the task), the
44 task scheduling delay (time between wakeup and actually running) and run
45 time for the task:
46 time cpu task name wait time sch delay run time
48 [tid/pid] (msec) (msec) (msec)
49 -------------- ------ -------------------- --------- --------- ---------
50 79371.874569 [0011] gcc[31949] 0.014 0.000 1.148
51 79371.874591 [0010] gcc[31951] 0.000 0.000 0.024
52 79371.874603 [0010] migration/10[59] 3.350 0.004 0.011
53 79371.874604 [0011] <idle> 1.148 0.000 0.035
54 79371.874723 [0005] <idle> 0.016 0.000 1.383
55 79371.874746 [0005] gcc[31949] 0.153 0.078 0.022
56 ...
57 Times are in msec.usec.
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61 -i, --input=<file>
62 Input file name. (default: perf.data unless stdin is a fifo)
63 -v, --verbose
65 Be more verbose. (show symbol address, etc)
66 -D, --dump-raw-trace=
68 Display verbose dump of the sched data.
69 -f, --force
71 Don’t complain, do it.
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74 --compact
75 Show only CPUs with activity. Helps visualizing on high core count
76 systems.
77 --cpus
79 Show just entries with activities for the given CPUs.
80 --color-cpus
82 Highlight the given cpus.
83 --color-pids
85 Highlight the given pids.
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88 -k, --vmlinux=<file>
89 vmlinux pathname
90 --kallsyms=<file>
92 kallsyms pathname
93 -g, --call-graph
95 Display call chains if present (default on).
96 --max-stack
98 Maximum number of functions to display in backtrace, default 5.
99 -p=, --pid=
101 Only show events for given process ID (comma separated list).
102 -t=, --tid=
104 Only show events for given thread ID (comma separated list).
105 -s, --summary
107 Show only a summary of scheduling by thread with min, max, and
108 average run times (in sec) and relative stddev.
109 -S, --with-summary
111 Show all scheduling events followed by a summary by thread with
112 min, max, and average run times (in sec) and relative stddev.
113 --symfs=<directory>
115 Look for files with symbols relative to this directory.
116 -V, --cpu-visual
118 Show visual aid for sched switches by CPU: i marks idle time, s are
119 scheduler events.
120 -w, --wakeups
122 Show wakeup events.
123 -M, --migrations
125 Show migration events.
126 -n, --next
128 Show next task.
129 -I, --idle-hist
131 Show idle-related events only.
132 --time
134 Only analyze samples within given time window: <start>,<stop>.
135 Times have the format seconds.microseconds. If start is not given
136 (i.e., time string is ,x.y) then analysis starts at the beginning
137 of the file. If stop time is not given (i.e, time string is x.y,)
138 then analysis goes to end of file.
139 --state
141 Show task state when it switched out.
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144 perf-record(1)
145perf 06/03/2019 PERF-SCHED(1)