On Tue, Dec 12, 2023 at 1:39 PM Yonghong Song <yonghong.song@xxxxxxxxx> wrote:
>
>
> On 12/12/23 10:29 AM, YiFei Zhu wrote:
> > We're observing test flakiness on an arm64 platform which might not
> > have timestamps as precise as x86. The test log looks like:
> >
> > test_time_tai:PASS:tai_open 0 nsec
> > test_time_tai:PASS:test_run 0 nsec
> > test_time_tai:PASS:tai_ts1 0 nsec
> > test_time_tai:PASS:tai_ts2 0 nsec
> > test_time_tai:FAIL:tai_forward unexpected tai_forward: actual 1702348135471494160 <= expected 1702348135471494160
> > test_time_tai:PASS:tai_gettime 0 nsec
> > test_time_tai:PASS:tai_future_ts1 0 nsec
> > test_time_tai:PASS:tai_future_ts2 0 nsec
> > test_time_tai:PASS:tai_range_ts1 0 nsec
> > test_time_tai:PASS:tai_range_ts2 0 nsec
> > #199 time_tai:FAIL
> >
> > This patch changes ASSERT_GT to ASSERT_GE in the tai_forward assertion
> > so that equal timestamps are permitted.
> >
> > Fixes: 64e15820b987 ("selftests/bpf: Add BPF-helper test for CLOCK_TAI access")
> > Signed-off-by: YiFei Zhu <zhuyifei@xxxxxxxxxx>
> > ---
> > tools/testing/selftests/bpf/prog_tests/time_tai.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/time_tai.c b/tools/testing/selftests/bpf/prog_tests/time_tai.c
> > index a31119823666..f45af1b0ef2c 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/time_tai.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/time_tai.c
> > @@ -56,7 +56,7 @@ void test_time_tai(void)
> > ASSERT_NEQ(ts2, 0, "tai_ts2");
> >
> > /* TAI is moving forward only */
> > - ASSERT_GT(ts2, ts1, "tai_forward");
> > + ASSERT_GE(ts2, ts1, "tai_forward");
>
> Can we guard the new change with arm64 specific macro?
Problem with this is that I'm not sure what other architectures could
be affected. AFAICT from the test, what it cares about is that time is
moving forwards rather than going backwards, so I thought GE is good
enough for what it's testing for.
>
> >
> > /* Check for future */
> > ret = clock_gettime(CLOCK_TAI, &now_tai);
