[PATCH v2 10/12] perf tests: Speed up off-cpu profiling tests

[Ian Rogers <irogers@google.com>]

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 99` and `sleep 0.1`.
- Change the below-threshold test to use `--off-cpu-thresh 120` and `sleep 0.1`.
- Update the awk period check in the above-threshold test to look for a period greater than 99,000,000 ns (99ms) 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.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/record_offcpu.sh | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/tests/shell/record_offcpu.sh b/tools/perf/tests/shell/record_offcpu.sh
index 860a2d6f4b75..8ee2112b7778 100755
--- a/tools/perf/tests/shell/record_offcpu.sh
+++ b/tools/perf/tests/shell/record_offcpu.sh
@@ -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 ${perfdata} sleep 0.1 2> /dev/null
   then
     echo "Basic off-cpu test [Failed record]"
     err=1
@@ -98,8 +98,8 @@ test_offcpu_child() {
 test_offcpu_above_thresh() {
   echo "${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
-- 
2.54.0.1136.gdb2ca164c4-goog