From: Nick Forrington <nick.forrington@arm.com>
Date: Thu, 2 Nov 2023 16:22:24 +0000 (+0000)
Subject: perf test: Remove atomics from test_loop to avoid test failures
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=72b4ca7e993e94f09bcf6d19fc385a2e8060c71f;p=linux.git

perf test: Remove atomics from test_loop to avoid test failures

The current use of atomics can lead to test failures, as tests (such as
tests/shell/record.sh) search for samples with "test_loop" as the
top-most stack frame, but find frames related to the atomic operation
(e.g. __aarch64_ldadd4_relax).

This change simply removes the "count" variable, as it is not necessary.

Fixes: 1962ab6f6e0b39e4 ("perf test workload thloop: Make count increments atomic")
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Nick Forrington <nick.forrington@arm.com>
Acked-by: Leo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20231102162225.50028-1-nick.forrington@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/tests/workloads/thloop.c b/tools/perf/tests/workloads/thloop.c
index af05269c2eb8a..457b29f91c3ee 100644
--- a/tools/perf/tests/workloads/thloop.c
+++ b/tools/perf/tests/workloads/thloop.c
@@ -7,7 +7,6 @@
 #include "../tests.h"
 
 static volatile sig_atomic_t done;
-static volatile unsigned count;
 
 /* We want to check this symbol in perf report */
 noinline void test_loop(void);
@@ -19,8 +18,7 @@ static void sighandler(int sig __maybe_unused)
 
 noinline void test_loop(void)
 {
-	while (!done)
-		__atomic_fetch_add(&count, 1, __ATOMIC_RELAXED);
+	while (!done);
 }
 
 static void *thfunc(void *arg)