1 perf-kwork(1)
2 =============
3
4 NAME
5 ----
6 perf-kwork - Tool to trace/measure kernel work properties (latencies)
7
8 SYNOPSIS
9 --------
10 [verse]
11 'perf kwork' {record|report|latency|timehist|top}
12
13 DESCRIPTION
14 -----------
15 There are several variants of 'perf kwork':
16
17 'perf kwork record <command>' to record the kernel work
18 of an arbitrary workload.
19
20 'perf kwork report' to report the per kwork runtime.
21
22 'perf kwork latency' to report the per kwork latencies.
23
24 'perf kwork timehist' provides an analysis of kernel work events.
25
26 'perf kwork top' to report the task cpu usage.
27
28 Example usage:
29 perf kwork record -- sleep 1
30 perf kwork report
31 perf kwork report -b
32 perf kwork latency
33 perf kwork latency -b
34 perf kwork timehist
35 perf kwork top
36 perf kwork top -b
37
38 By default it shows the individual work events such as irq, workqueue,
39 including the run time and delay (time between raise and actually entry):
40
41 Runtime start Runtime end Cpu Kwork name Runtime Delaytime
42 (TYPE)NAME:NUM (msec) (msec)
43 ----------------- ----------------- ------ ------------------------- ---------- ----------
44 1811186.976062 1811186.976327 [0000] (s)RCU:9 0.266 0.114
45 1811186.978452 1811186.978547 [0000] (s)SCHED:7 0.095 0.171
46 1811186.980327 1811186.980490 [0000] (s)SCHED:7 0.162 0.083
47 1811186.981221 1811186.981271 [0000] (s)SCHED:7 0.050 0.077
48 1811186.984267 1811186.984318 [0000] (s)SCHED:7 0.051 0.075
49 1811186.987252 1811186.987315 [0000] (s)SCHED:7 0.063 0.081
50 1811186.987785 1811186.987843 [0006] (s)RCU:9 0.058 0.645
51 1811186.988319 1811186.988383 [0000] (s)SCHED:7 0.064 0.143
52 1811186.989404 1811186.989607 [0002] (s)TIMER:1 0.203 0.111
53 1811186.989660 1811186.989732 [0002] (s)SCHED:7 0.072 0.310
54 1811186.991295 1811186.991407 [0002] eth0:10 0.112
55 1811186.991639 1811186.991734 [0002] (s)NET_RX:3 0.095 0.277
56 1811186.989860 1811186.991826 [0002] (w)vmstat_shepherd 1.966 0.345
57 ...
58
59 Times are in msec.usec.
60
61 OPTIONS
62 -------
63 -D::
64 --dump-raw-trace=::
65 Display verbose dump of the sched data.
66
67 -f::
68 --force::
69 Don't complain, do it.
70
71 -k::
72 --kwork::
73 List of kwork to profile (irq, softirq, workqueue, sched, etc)
74
75 -v::
76 --verbose::
77 Be more verbose. (show symbol address, etc)
78
79 OPTIONS for 'perf kwork report'
80 ----------------------------
81
82 -b::
83 --use-bpf::
84 Use BPF to measure kwork runtime
85
86 -C::
87 --cpu::
88 Only show events for the given CPU(s) (comma separated list).
89
90 -i::
91 --input::
92 Input file name. (default: perf.data unless stdin is a fifo)
93
94 -n::
95 --name::
96 Only show events for the given name.
97
98 -s::
99 --sort::
100 Sort by key(s): runtime, max, count
101
102 -S::
103 --with-summary::
104 Show summary with statistics
105
106 --time::
107 Only analyze samples within given time window: <start>,<stop>. Times
108 have the format seconds.microseconds. If start is not given (i.e., time
109 string is ',x.y') then analysis starts at the beginning of the file. If
110 stop time is not given (i.e, time string is 'x.y,') then analysis goes
111 to end of file.
112
113 OPTIONS for 'perf kwork latency'
114 ----------------------------
115
116 -b::
117 --use-bpf::
118 Use BPF to measure kwork latency
119
120 -C::
121 --cpu::
122 Only show events for the given CPU(s) (comma separated list).
123
124 -i::
125 --input::
126 Input file name. (default: perf.data unless stdin is a fifo)
127
128 -n::
129 --name::
130 Only show events for the given name.
131
132 -s::
133 --sort::
134 Sort by key(s): avg, max, count
135
136 --time::
137 Only analyze samples within given time window: <start>,<stop>. Times
138 have the format seconds.microseconds. If start is not given (i.e., time
139 string is ',x.y') then analysis starts at the beginning of the file. If
140 stop time is not given (i.e, time string is 'x.y,') then analysis goes
141 to end of file.
142
143 OPTIONS for 'perf kwork timehist'
144 ---------------------------------
145
146 -C::
147 --cpu::
148 Only show events for the given CPU(s) (comma separated list).
149
150 -g::
151 --call-graph::
152 Display call chains if present (default off).
153
154 -i::
155 --input::
156 Input file name. (default: perf.data unless stdin is a fifo)
157
158 -k::
159 --vmlinux=<file>::
160 Vmlinux pathname
161
162 -n::
163 --name::
164 Only show events for the given name.
165
166 --kallsyms=<file>::
167 Kallsyms pathname
168
169 --max-stack::
170 Maximum number of functions to display in backtrace, default 5.
171
172 --symfs=<directory>::
173 Look for files with symbols relative to this directory.
174
175 --time::
176 Only analyze samples within given time window: <start>,<stop>. Times
177 have the format seconds.microseconds. If start is not given (i.e., time
178 string is ',x.y') then analysis starts at the beginning of the file. If
179 stop time is not given (i.e, time string is 'x.y,') then analysis goes
180 to end of file.
181
182 OPTIONS for 'perf kwork top'
183 ---------------------------------
184
185 -b::
186 --use-bpf::
187 Use BPF to measure task cpu usage.
188
189 -C::
190 --cpu::
191 Only show events for the given CPU(s) (comma separated list).
192
193 -i::
194 --input::
195 Input file name. (default: perf.data unless stdin is a fifo)
196
197 -n::
198 --name::
199 Only show events for the given name.
200
201 -s::
202 --sort::
203 Sort by key(s): rate, runtime, tid
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 SEE ALSO
213 --------
214 linkperf:perf-record[1]
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