Commit 3178155d authored by James Clark's avatar James Clark Committed by Arnaldo Carvalho de Melo
Browse files

perf test brstack: Speed up running test by using tr -s instead of xargs 



The brstack test runs quite slowly in software models. Part of the reason
is "xargs -n1" is quite inefficient in replacing spaces with newlines.

While that's not noticeable on normal machines, it is on software models.

Use "tr -s ' ' '\n'" instead which can do the same transformation, but is
much faster. For comparison on an M1 Macbook Pro:

  $ time seq -s ' ' 10000 | xargs -n1 > /dev/null

  real    0m2.729s
  user    0m2.009s
  sys     0m0.914s
  $ time seq -s ' ' 10000 | tr -s ' ' '\n' | grep '.' > /dev/null

  real    0m0.002s
  user    0m0.001s
  sys     0m0.001s

The "grep '.'" is also needed to remove any remaining blank lines.

Signed-off-by: default avatarJames Clark <james.clark@arm.com>
Reviewed-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: default avatarJames Clark <james.clark@linaro.org>
Reviewed-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241213231312.2640687-2-robh@kernel.org


Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
[robh: Drop changing loop iterations on arm64. Squash blank line fix and redo commit msg]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b1bb6fc0

tools/perf/tests/shell/test_brstack.sh

+2 −2
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ test_user_branches() { 
	echo "Testing user branch stack sampling"



	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- ${TESTPROG} > /dev/null 2>&1

	perf script -i $TMPDIR/perf.data --fields brstacksym | xargs -n1 > $TMPDIR/perf.script

	perf script -i $TMPDIR/perf.data --fields brstacksym | tr -s ' ' '\n' > $TMPDIR/perf.script



	# example of branch entries:

	# 	brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL
@@ -59,7 +59,7 @@ test_filter() { 
	echo "Testing branch stack filtering permutation ($test_filter_filter,$test_filter_expect)"



	perf record -o $TMPDIR/perf.data --branch-filter $test_filter_filter,save_type,u -- ${TESTPROG} > /dev/null 2>&1

	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script

	perf script -i $TMPDIR/perf.data --fields brstack | tr -s ' ' '\n' | grep '.' > $TMPDIR/perf.script



	# fail if we find any branch type that doesn't match any of the expected ones

	# also consider UNKNOWN branch types (-)