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 LBR tests (exclusive)
3# SPDX-License-Identifier: GPL-2.0
4
5set -e
6
7ParanoidAndNotRoot() {
8 [ "$(id -u)" != 0 ] && [ "$(cat /proc/sys/kernel/perf_event_paranoid)" -gt $1 ]
9}
10
11if [ ! -f /sys/bus/event_source/devices/cpu/caps/branches ] &&
12 [ ! -f /sys/bus/event_source/devices/cpu_core/caps/branches ]
13then
14 echo "Skip: only x86 CPUs support LBR"
15 exit 2
16fi
17
18err=0
19perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
20
21cleanup() {
22 rm -rf "${perfdata}"
23 rm -rf "${perfdata}".old
24 rm -rf "${perfdata}".txt
25
26 trap - EXIT TERM INT
27}
28
29trap_cleanup() {
30 echo "Unexpected signal in ${FUNCNAME[1]}"
31 cleanup
32 exit 1
33}
34trap trap_cleanup EXIT TERM INT
35
36
37lbr_callgraph_test() {
38 test="LBR callgraph"
39
40 echo "$test"
41 if ! perf record -e cycles --call-graph lbr -o "${perfdata}" perf test -w thloop
42 then
43 echo "$test [Failed support missing]"
44 if [ $err -eq 0 ]
45 then
46 err=2
47 fi
48 return
49 fi
50
51 if ! perf report --stitch-lbr -i "${perfdata}" > "${perfdata}".txt
52 then
53 cat "${perfdata}".txt
54 echo "$test [Failed in perf report]"
55 err=1
56 return
57 fi
58
59 echo "$test [Success]"
60}
61
62lbr_test() {
63 local branch_flags=$1
64 local test="LBR $2 test"
65 local threshold=$3
66 local out
67 local sam_nr
68 local bs_nr
69 local zero_nr
70 local r
71
72 echo "$test"
73 if ! perf record -e cycles $branch_flags -o "${perfdata}" perf test -w thloop
74 then
75 echo "$test [Failed support missing]"
76 perf record -e cycles $branch_flags -o "${perfdata}" perf test -w thloop || true
77 if [ $err -eq 0 ]
78 then
79 err=2
80 fi
81 return
82 fi
83
84 out=$(perf report -D -i "${perfdata}" 2> /dev/null | grep -A1 'PERF_RECORD_SAMPLE')
85 sam_nr=$(echo "$out" | grep -c 'PERF_RECORD_SAMPLE' || true)
86 if [ $sam_nr -eq 0 ]
87 then
88 echo "$test [Failed no samples captured]"
89 err=1
90 return
91 fi
92 echo "$test: $sam_nr samples"
93
94 bs_nr=$(echo "$out" | grep -c 'branch stack: nr:' || true)
95 if [ $sam_nr -ne $bs_nr ]
96 then
97 echo "$test [Failed samples missing branch stacks]"
98 err=1
99 return
100 fi
101
102 zero_nr=$(echo "$out" | grep -A3 'branch stack: nr:0' | grep thread | grep -cv swapper || true)
103 r=$(($zero_nr * 100 / $bs_nr))
104 if [ $r -gt $threshold ]; then
105 echo "$test [Failed empty br stack ratio exceed $threshold%: $r%]"
106 err=1
107 return
108 fi
109
110 echo "$test [Success]"
111}
112
113parallel_lbr_test() {
114 err=0
115 perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
116 lbr_test "$1" "$2" "$3"
117 cleanup
118 exit $err
119}
120
121lbr_callgraph_test
122
123# Sequential
124lbr_test "-b" "any branch" 2
125lbr_test "-j any_call" "any call" 2
126lbr_test "-j any_ret" "any ret" 2
127lbr_test "-j ind_call" "any indirect call" 2
128lbr_test "-j ind_jmp" "any indirect jump" 100
129lbr_test "-j call" "direct calls" 2
130lbr_test "-j ind_call,u" "any indirect user call" 100
131if ! ParanoidAndNotRoot 1
132then
133 lbr_test "-a -b" "system wide any branch" 2
134 lbr_test "-a -j any_call" "system wide any call" 2
135fi
136
137# Parallel
138parallel_lbr_test "-b" "parallel any branch" 100 &
139pid1=$!
140parallel_lbr_test "-j any_call" "parallel any call" 100 &
141pid2=$!
142parallel_lbr_test "-j any_ret" "parallel any ret" 100 &
143pid3=$!
144parallel_lbr_test "-j ind_call" "parallel any indirect call" 100 &
145pid4=$!
146parallel_lbr_test "-j ind_jmp" "parallel any indirect jump" 100 &
147pid5=$!
148parallel_lbr_test "-j call" "parallel direct calls" 100 &
149pid6=$!
150parallel_lbr_test "-j ind_call,u" "parallel any indirect user call" 100 &
151pid7=$!
152if ParanoidAndNotRoot 1
153then
154 pid8=
155 pid9=
156else
157 parallel_lbr_test "-a -b" "parallel system wide any branch" 100 &
158 pid8=$!
159 parallel_lbr_test "-a -j any_call" "parallel system wide any call" 100 &
160 pid9=$!
161fi
162
163for pid in $pid1 $pid2 $pid3 $pid4 $pid5 $pid6 $pid7 $pid8 $pid9
164do
165 set +e
166 wait $pid
167 child_err=$?
168 set -e
169 if ([ $err -eq 2 ] && [ $child_err -eq 1 ]) || [ $err -eq 0 ]
170 then
171 err=$child_err
172 fi
173done
174
175cleanup
176exit $err