selftests/bpf: Reduce flakyness in timer_mim

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210823213629.3519641-1-fallentree@fb.com

diff --git a/tools/testing/selftests/bpf/prog_tests/timer_mim.c b/tools/testing/selftests/bpf/prog_tests/timer_mim.c
index f5acbcbe33a4f847faa57673d6a606d26e31c0e7..ced8f6cf347cdfc0203f0ac9e1adbe054581367a 100644 (file)
--- 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;