On Thu, Mar 12, 2020 at 11:18:37PM -0700, Andrii Nakryiko wrote:
> nanosleep syscall expects pointer to struct timespec, not nanoseconds
> directly. Current implementation fulfills its purpose of invoking nanosleep
> syscall, but doesn't really provide sleeping capabilities, which can cause
> flakiness for tests relying on usleep() to wait for something.
>
> Fixes: ec12a57b822c ("selftests/bpf: Guarantee that useep() calls nanosleep() syscall")
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
> tools/testing/selftests/bpf/test_progs.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index 2b0bc1171c9c..b6201dd82edf 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -35,7 +35,16 @@ struct prog_test_def {
> */
> int usleep(useconds_t usec)
> {
> - return syscall(__NR_nanosleep, usec * 1000UL);
> + struct timespec ts;
> +
> + if (usec > 999999) {
> + ts.tv_sec = usec / 1000000;
> + ts.tv_nsec = usec % 1000000;
> + } else {
> + ts.tv_sec = 0;
> + ts.tv_nsec = usec;
> + }
> + return nanosleep(&ts, NULL);
> }
Is this a copy-paste from somewhere?
Above 'if' looks like premature optimization.
I applied it anyway, since it fixes flakiness in test_progs -n 24.
Now pin*tp* tests are stable.
But the other one is still flaky:
server_thread:FAIL:237
Failed to accept client: Resource temporarily unavailable
#64 tcp_rtt:FAIL
Note that if I run the test alone (test_progs -n 64) it is stable.
It fails only when run as part of bigger test_progs.
test_progs -n 30-64 sporadically fails (most of the time)
test_progs -n 40-64 consistently passes
Haven't bisected further.
