1PERF-KOWRK(1) perf Manual PERF-KOWRK(1)
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6 perf-kwork - Tool to trace/measure kernel work properties (latencies)
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9 perf kwork {record|report|latency|timehist}
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12 There are several variants of perf kwork:
13 'perf kwork record <command>' to record the kernel work
15 of an arbitrary workload.
16 'perf kwork report' to report the per kwork runtime.
18 'perf kwork latency' to report the per kwork latencies.
20 'perf kwork timehist' provides an analysis of kernel work events.
22 Example usage:
24 perf kwork record -- sleep 1
25 perf kwork report
26 perf kwork report -b
27 perf kwork latency
28 perf kwork latency -b
29 perf kwork timehist
30 By default it shows the individual work events such as irq, workqeueu,
32 including the run time and delay (time between raise and actually entry):
33 Runtime start Runtime end Cpu Kwork name Runtime Delaytime
35 (TYPE)NAME:NUM (msec) (msec)
36 ----------------- ----------------- ------ ------------------------- ---------- ----------
37 1811186.976062 1811186.976327 [0000] (s)RCU:9 0.266 0.114
38 1811186.978452 1811186.978547 [0000] (s)SCHED:7 0.095 0.171
39 1811186.980327 1811186.980490 [0000] (s)SCHED:7 0.162 0.083
40 1811186.981221 1811186.981271 [0000] (s)SCHED:7 0.050 0.077
41 1811186.984267 1811186.984318 [0000] (s)SCHED:7 0.051 0.075
42 1811186.987252 1811186.987315 [0000] (s)SCHED:7 0.063 0.081
43 1811186.987785 1811186.987843 [0006] (s)RCU:9 0.058 0.645
44 1811186.988319 1811186.988383 [0000] (s)SCHED:7 0.064 0.143
45 1811186.989404 1811186.989607 [0002] (s)TIMER:1 0.203 0.111
46 1811186.989660 1811186.989732 [0002] (s)SCHED:7 0.072 0.310
47 1811186.991295 1811186.991407 [0002] eth0:10 0.112
48 1811186.991639 1811186.991734 [0002] (s)NET_RX:3 0.095 0.277
49 1811186.989860 1811186.991826 [0002] (w)vmstat_shepherd 1.966 0.345
50 ...
51 Times are in msec.usec.
53
55 -D, --dump-raw-trace=
56 Display verbose dump of the sched data.
57 -f, --force
59 Don’t complain, do it.
60 -k, --kwork
62 List of kwork to profile (irq, softirq, workqueue, etc)
63 -v, --verbose
65 Be more verbose. (show symbol address, etc)
66 OPTIONS for perf kwork report
68 .ft C
71 -b::
72 --use-bpf::
73 Use BPF to measure kwork runtime
74 -C::
76 --cpu::
77 Only show events for the given CPU(s) (comma separated list).
78 -i::
80 --input::
81 Input file name. (default: perf.data unless stdin is a fifo)
82 -n::
84 --name::
85 Only show events for the given name.
86 -s::
88 --sort::
89 Sort by key(s): runtime, max, count
90 -S::
92 --with-summary::
93 Show summary with statistics
94 --time::
96 Only analyze samples within given time window: <start>,<stop>. Times
97 have the format seconds.microseconds. If start is not given (i.e., time
98 string is ',x.y') then analysis starts at the beginning of the file. If
99 stop time is not given (i.e, time string is 'x.y,') then analysis goes
100 to end of file.
101 OPTIONS for 'perf kwork latency'
103 .ft
104 -b, --use-bpf
107 Use BPF to measure kwork latency
108 -C, --cpu
110 Only show events for the given CPU(s) (comma separated list).
111 -i, --input
113 Input file name. (default: perf.data unless stdin is a fifo)
114 -n, --name
116 Only show events for the given name.
117 -s, --sort
119 Sort by key(s): avg, max, count
120 --time
122 Only analyze samples within given time window: <start>,<stop>.
123 Times have the format seconds.microseconds. If start is not given
124 (i.e., time string is ,x.y) then analysis starts at the beginning
125 of the file. If stop time is not given (i.e, time string is x.y,)
126 then analysis goes to end of file.
127
129 -C, --cpu
130 Only show events for the given CPU(s) (comma separated list).
131 -g, --call-graph
133 Display call chains if present (default off).
134 -i, --input
136 Input file name. (default: perf.data unless stdin is a fifo)
137 -k, --vmlinux=<file>
139 Vmlinux pathname
140 -n, --name
142 Only show events for the given name.
143 --kallsyms=<file>
145 Kallsyms pathname
146 --max-stack
148 Maximum number of functions to display in backtrace, default 5.
149 --symfs=<directory>
151 Look for files with symbols relative to this directory.
152 --time
154 Only analyze samples within given time window: <start>,<stop>.
155 Times have the format seconds.microseconds. If start is not given
156 (i.e., time string is ,x.y) then analysis starts at the beginning
157 of the file. If stop time is not given (i.e, time string is x.y,)
158 then analysis goes to end of file.
159
161 perf-record(1)
162perf 11/28/2023 PERF-KOWRK(1)