1perf-kowrk(1)
2=============
3
4NAME
5----
6perf-kwork - Tool to trace/measure kernel work properties (latencies)
7
8SYNOPSIS
9--------
10[verse]
11'perf kwork' {record|report|latency|timehist|top}
12
13DESCRIPTION
14-----------
15There 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, workqeueu,
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
61OPTIONS
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
79OPTIONS 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
113OPTIONS 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
143OPTIONS 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
182OPTIONS 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
212SEE ALSO
213--------
214linkperf:perf-record[1]
215