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
77OPTIONS for 'perf sched map'
78----------------------------
79
80--compact::
81	Show only CPUs with activity. Helps visualizing on high core
82	count systems.
83
84--cpus::
85	Show just entries with activities for the given CPUs.
86
87--color-cpus::
88	Highlight the given cpus.
89
90--color-pids::
91	Highlight the given pids.
92
93OPTIONS for 'perf sched timehist'
94---------------------------------
95-k::
96--vmlinux=<file>::
97    vmlinux pathname
98
99--kallsyms=<file>::
100    kallsyms pathname
101
102-g::
103--no-call-graph::
104	Do not display call chains if present.
105
106--max-stack::
107	Maximum number of functions to display in backtrace, default 5.
108
109-p=::
110--pid=::
111	Only show events for given process ID (comma separated list).
112
113-t=::
114--tid=::
115	Only show events for given thread ID (comma separated list).
116
117-s::
118--summary::
119    Show only a summary of scheduling by thread with min, max, and average
120    run times (in sec) and relative stddev.
121
122-S::
123--with-summary::
124    Show all scheduling events followed by a summary by thread with min,
125    max, and average run times (in sec) and relative stddev.
126
127--symfs=<directory>::
128    Look for files with symbols relative to this directory.
129
130-V::
131--cpu-visual::
132	Show visual aid for sched switches by CPU: 'i' marks idle time,
133	's' are scheduler events.
134
135-w::
136--wakeups::
137	Show wakeup events.
138
139-M::
140--migrations::
141	Show migration events.
142
143-n::
144--next::
145	Show next task.
146
147-I::
148--idle-hist::
149	Show idle-related events only.
150
151--time::
152	Only analyze samples within given time window: <start>,<stop>. Times
153	have the format seconds.microseconds. If start is not given (i.e., time
154	string is ',x.y') then analysis starts at the beginning of the file. If
155	stop time is not given (i.e, time string is 'x.y,') then analysis goes
156	to end of file.
157
158--state::
159	Show task state when it switched out.
160
161SEE ALSO
162--------
163linkperf:perf-record[1]
164