[PATCH bpf-next] selftests/bpf: reduce flakyness in timer_mim

[PATCH bpf-next] selftests/bpf: reduce flakyness in timer_mim

[Yucong Sun]

This patch extends wait time in timer_mim. As observed in slow CI environment,
it is possible to have interrupt/preemption long enough to cause the test to
fail, almost 1 failure in 5 runs.

Signed-off-by: Yucong Sun <fallentree@fb.com>
---
 .../testing/selftests/bpf/prog_tests/timer_mim.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/timer_mim.c b/tools/testing/selftests/bpf/prog_tests/timer_mim.c
index f5acbcbe33a4..ced8f6cf347c 100644
--- a/tools/testing/selftests/bpf/prog_tests/timer_mim.c
+++ b/tools/testing/selftests/bpf/prog_tests/timer_mim.c
@@ -23,8 +23,12 @@ static int timer_mim(struct timer_mim *timer_skel)
 
 	/* check that timer_cb[12] are incrementing 'cnt' */
 	cnt1 = READ_ONCE(timer_skel->bss->cnt);
-	usleep(200); /* 100 times more than interval */
-	cnt2 = READ_ONCE(timer_skel->bss->cnt);
+	for (int i = 0; i < 100; i++) {
+		cnt2 = READ_ONCE(timer_skel->bss->cnt);
+		if (cnt2 != cnt1)
+			break;
+		usleep(200); /* 100 times more than interval */
+	}
 	ASSERT_GT(cnt2, cnt1, "cnt");
 
 	ASSERT_EQ(timer_skel->bss->err, 0, "err");
@@ -37,8 +41,12 @@ static int timer_mim(struct timer_mim *timer_skel)
 
 	/* check that timer_cb[12] are no longer running */
 	cnt1 = READ_ONCE(timer_skel->bss->cnt);
-	usleep(200);
-	cnt2 = READ_ONCE(timer_skel->bss->cnt);
+	for (int i = 0; i < 100; i++) {
+		usleep(200); /* 100 times more than interval */
+		cnt2 = READ_ONCE(timer_skel->bss->cnt);
+		if (cnt2 == cnt1)
+			break;
+	}
 	ASSERT_EQ(cnt2, cnt1, "cnt");
 
 	return 0;
-- 
2.30.2