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| author | Li Wang <liwang@redhat.com> | 2022-03-29 13:03:51 +0800 |
|---|---|---|
| committer | Cixi Geng <cixi.geng1@unisoc.com> | 2022-10-14 11:18:53 +0800 |
| commit | d3d9c6ef37991fe92d3c81c13be97d52cf4eaa84 (patch) | |
| tree | 416c0654b652509ffc70e3b7ab0b238c3e0ead3c | |
| parent | b4d33ed0ef791f819f66071f68e5cd897bee27c5 (diff) | |
| download | ltp-d3d9c6ef37991fe92d3c81c13be97d52cf4eaa84.tar.gz | |
BACKPORT: clock_gettime04: set threshold based on the clock resolution
This is to get rid of the intermittent failures in clock_gettime04,
which are likely caused by different clock tick rates on platforms.
Here give two thresholds (in milliseconds) for comparison, one for
COARSE clock and one for the rest.
Error log:
clock_gettime04.c:163: TFAIL: CLOCK_REALTIME_COARSE(syscall with old kernel spec):
Difference between successive readings greater than 5 ms (1): 10
clock_gettime04.c:163: TFAIL: CLOCK_MONOTONIC_COARSE(vDSO with old kernel spec):
Difference between successive readings greater than 5 ms (2): 10
From Waiman Long:
That failure happens for CLOCK_REALTIME_COARSE which is a faster but less
precise version of CLOCK_REALTIME. The time resolution is actually a clock
tick. Since arm64 has a HZ rate of 100. That means each tick is 10ms. So a
CLOCK_REALTIME_COARSE threshold of 5ms is probably not enough. I would say
in the case of CLOCK_REALTIME_COARSE, we have to increase the threshold based
on the clock tick rate of the system. This is more a test failure than is
an inherent problem in the kernel.
Fixes #898
Reported-by: Eirik Fuller <efuller@redhat.com>
Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
Acked-by: Waiman Long <longman@redhat.com>
Bug: 253210281
Change-Id: I2a5145c791f3f8b99ce7f3b4015845e01aad17a7
Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
| -rw-r--r-- | testcases/kernel/syscalls/clock_gettime/clock_gettime04.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c index a8d2c5b38..c279da79e 100644 --- a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c +++ b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c @@ -35,7 +35,7 @@ clockid_t clks[] = { }; static gettime_t ptr_vdso_gettime, ptr_vdso_gettime64; -static long long delta = 5; +static long long delta, precise_delta, coarse_delta; static inline int do_vdso_gettime(gettime_t vdso, clockid_t clk_id, void *ts) { @@ -92,9 +92,18 @@ static struct time64_variants variants[] = { static void setup(void) { + struct timespec res; + + clock_getres(CLOCK_REALTIME, &res); + precise_delta = 5 + res.tv_nsec / 1000000; + + clock_getres(CLOCK_REALTIME_COARSE, &res); + coarse_delta = 5 + res.tv_nsec / 1000000; + if (tst_is_virt(VIRT_ANY)) { tst_res(TINFO, "Running in a virtual machine, multiply the delta by 10."); - delta *= 10; + precise_delta *= 10; + coarse_delta *= 10; } find_clock_gettime_vdso(&ptr_vdso_gettime, &ptr_vdso_gettime64); @@ -108,6 +117,11 @@ static void run(unsigned int i) int count = 10000, ret; unsigned int j; + if (clks[i] == CLOCK_REALTIME_COARSE || clks[i] == CLOCK_MONOTONIC_COARSE) + delta = coarse_delta; + else + delta = precise_delta; + do { for (j = 0; j < ARRAY_SIZE(variants); j++) { /* Refresh time in start */ |