mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-30 12:13:51 -04:00
Code Issues Packages Projects Releases Wiki Activity

perf tests: Speed up off-cpu profiling tests

Browse Source 
The off-cpu profiling test suite runs multiple recording commands with a
default workload of `sleep 1` to test the off-cpu threshold configurations
(specifically, above 999ms and below 1200ms). This adds a mandatory 3.0
seconds of sleep overhead.

Optimize this by scaling down the thresholds and workload durations by a
factor of 10:
- Use `sleep 0.1` as the workload duration.
- Change the above-threshold test to use `--off-cpu-thresh 50` and `sleep
  0.1`.
- Change the below-threshold test to use `--off-cpu-thresh 500` and `sleep
  0.1`.
- Update the awk period check in the above-threshold test to look for a
  period greater than 50,000,000 ns (50ms) instead of 999,000,000 ns
  (999ms).

This reduces raw test sleep overhead from 3.0s down to 0.3s, yielding a
~2.7 second speedup for this test.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Ian Rogers
2026-06-22 18:27:55 -07:00
committed by Namhyung Kim
parent 344d3aec16
commit c10f33fa66
1 changed files with 7 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
tools/perf/tests/shell/record_offcpu.sh
View File

@@ -45,7 +45,7 @@ test_offcpu_priv() {
test_offcpu_basic() {
echo "Basic off-cpu test"
if ! perf record --off-cpu -e dummy -o ${perfdata} sleep 1 2> /dev/null
if ! perf record --off-cpu -e dummy -o ${perfdata} sleep 0.3 2> /dev/null
then
echo "Basic off-cpu test [Failed record]"
err=1
@@ -57,7 +57,7 @@ test_offcpu_basic() {
err=1
return
fi
if ! perf report -i ${perfdata} -q --percent-limit=90 | grep -E -q sleep
if ! perf report -i ${perfdata} -q --percent-limit=70 | grep -E -q sleep
then
echo "Basic off-cpu test [Failed missing output]"
err=1
@@ -98,8 +98,8 @@ test_offcpu_child() {
test_offcpu_above_thresh() {
echo "${test_above_thresh}"
# collect direct off-cpu samples for tasks blocked for more than 999ms
if ! perf record -e dummy --off-cpu --off-cpu-thresh 999 -o ${perfdata} -- sleep 1 2> /dev/null
# collect direct off-cpu samples for tasks blocked for more than 50ms
if ! perf record -e dummy --off-cpu --off-cpu-thresh 50 -o ${perfdata} -- sleep 0.1 2> /dev/null
then
echo "${test_above_thresh} [Failed record]"
err=1
@@ -115,7 +115,7 @@ test_offcpu_above_thresh() {
fi
# there should only be one direct sample, and its period should be higher than off-cpu-thresh
if ! perf script --time "0, ${dummy_timestamp}" -i ${perfdata} -F period | \
awk '{ if (int($1) > 999000000) exit 0; else exit 1; }'
awk '{ if (int($1) > 50000000) exit 0; else exit 1; }'
then
echo "${test_above_thresh} [Failed off-cpu time too short]"
err=1
@@ -128,8 +128,8 @@ test_offcpu_above_thresh() {
test_offcpu_below_thresh() {
echo "${test_below_thresh}"
# collect direct off-cpu samples for tasks blocked for more than 1.2s
if ! perf record -e dummy --off-cpu --off-cpu-thresh 1200 -o ${perfdata} -- sleep 1 2> /dev/null
# collect direct off-cpu samples for tasks blocked for more than 500ms
if ! perf record -e dummy --off-cpu --off-cpu-thresh 500 -o ${perfdata} -- sleep 0.1 2> /dev/null
then
echo "${test_below_thresh} [Failed record]"
err=1