Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1#!/bin/bash
2# perf record offcpu profiling tests (exclusive)
3# SPDX-License-Identifier: GPL-2.0
4
5set -e
6
7err=0
8perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
9
10ts=$(printf "%u" $((~0 << 32))) # OFF_CPU_TIMESTAMP
11dummy_timestamp=${ts%???} # remove the last 3 digits to match perf script
12
13cleanup() {
14 rm -f ${perfdata}
15 rm -f ${perfdata}.old
16 trap - EXIT TERM INT
17}
18
19trap_cleanup() {
20 cleanup
21 exit 1
22}
23trap trap_cleanup EXIT TERM INT
24
25test_above_thresh="Threshold test (above threshold)"
26test_below_thresh="Threshold test (below threshold)"
27
28test_offcpu_priv() {
29 echo "Checking off-cpu privilege"
30
31 if [ "$(id -u)" != 0 ]
32 then
33 echo "off-cpu test [Skipped permission]"
34 err=2
35 return
36 fi
37 if perf version --build-options 2>&1 | grep HAVE_BPF_SKEL | grep -q OFF
38 then
39 echo "off-cpu test [Skipped missing BPF support]"
40 err=2
41 return
42 fi
43}
44
45test_offcpu_basic() {
46 echo "Basic off-cpu test"
47
48 if ! perf record --off-cpu -e dummy -o ${perfdata} sleep 1 2> /dev/null
49 then
50 echo "Basic off-cpu test [Failed record]"
51 err=1
52 return
53 fi
54 if ! perf evlist -i ${perfdata} | grep -q "offcpu-time"
55 then
56 echo "Basic off-cpu test [Failed no event]"
57 err=1
58 return
59 fi
60 if ! perf report -i ${perfdata} -q --percent-limit=90 | grep -E -q sleep
61 then
62 echo "Basic off-cpu test [Failed missing output]"
63 err=1
64 return
65 fi
66 echo "Basic off-cpu test [Success]"
67}
68
69test_offcpu_child() {
70 echo "Child task off-cpu test"
71
72 # perf bench sched messaging creates 400 processes
73 if ! perf record --off-cpu -e dummy -o ${perfdata} -- \
74 perf bench sched messaging -g 10 > /dev/null 2>&1
75 then
76 echo "Child task off-cpu test [Failed record]"
77 err=1
78 return
79 fi
80 if ! perf evlist -i ${perfdata} | grep -q "offcpu-time"
81 then
82 echo "Child task off-cpu test [Failed no event]"
83 err=1
84 return
85 fi
86 # each process waits at least for poll, so it should be more than 400 events
87 if ! perf report -i ${perfdata} -s comm -q -n -t ';' --percent-limit=90 | \
88 awk -F ";" '{ if (NF > 3 && int($3) < 400) exit 1; }'
89 then
90 echo "Child task off-cpu test [Failed invalid output]"
91 err=1
92 return
93 fi
94 echo "Child task off-cpu test [Success]"
95}
96
97# task blocks longer than the --off-cpu-thresh, perf should collect a direct sample
98test_offcpu_above_thresh() {
99 echo "${test_above_thresh}"
100
101 # collect direct off-cpu samples for tasks blocked for more than 999ms
102 if ! perf record -e dummy --off-cpu --off-cpu-thresh 999 -o ${perfdata} -- sleep 1 2> /dev/null
103 then
104 echo "${test_above_thresh} [Failed record]"
105 err=1
106 return
107 fi
108 # direct sample's timestamp should be lower than the dummy_timestamp of the at-the-end sample
109 # check if a direct sample exists
110 if ! perf script --time "0, ${dummy_timestamp}" -i ${perfdata} -F event | grep -q "offcpu-time"
111 then
112 echo "${test_above_thresh} [Failed missing direct samples]"
113 err=1
114 return
115 fi
116 # there should only be one direct sample, and its period should be higher than off-cpu-thresh
117 if ! perf script --time "0, ${dummy_timestamp}" -i ${perfdata} -F period | \
118 awk '{ if (int($1) > 999000000) exit 0; else exit 1; }'
119 then
120 echo "${test_above_thresh} [Failed off-cpu time too short]"
121 err=1
122 return
123 fi
124 echo "${test_above_thresh} [Success]"
125}
126
127# task blocks shorter than the --off-cpu-thresh, perf should collect an at-the-end sample
128test_offcpu_below_thresh() {
129 echo "${test_below_thresh}"
130
131 # collect direct off-cpu samples for tasks blocked for more than 1.2s
132 if ! perf record -e dummy --off-cpu --off-cpu-thresh 1200 -o ${perfdata} -- sleep 1 2> /dev/null
133 then
134 echo "${test_below_thresh} [Failed record]"
135 err=1
136 return
137 fi
138 # see if there's an at-the-end sample
139 if ! perf script --time "${dummy_timestamp}," -i ${perfdata} -F event | grep -q 'offcpu-time'
140 then
141 echo "${test_below_thresh} [Failed at-the-end samples cannot be found]"
142 err=1
143 return
144 fi
145 # plus there shouldn't be any direct samples
146 if perf script --time "0, ${dummy_timestamp}" -i ${perfdata} -F event | grep -q 'offcpu-time'
147 then
148 echo "${test_below_thresh} [Failed direct samples are found when they shouldn't be]"
149 err=1
150 return
151 fi
152 echo "${test_below_thresh} [Success]"
153}
154
155test_offcpu_priv
156
157if [ $err = 0 ]; then
158 test_offcpu_basic
159fi
160
161if [ $err = 0 ]; then
162 test_offcpu_child
163fi
164
165if [ $err = 0 ]; then
166 test_offcpu_above_thresh
167fi
168
169if [ $err = 0 ]; then
170 test_offcpu_below_thresh
171fi
172
173cleanup
174exit $err