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| author | Jan Stancek <jstancek@redhat.com> | 2021-07-23 14:24:52 +0200 |
|---|---|---|
| committer | Edward Liaw <edliaw@google.com> | 2024-01-05 00:33:52 +0000 |
| commit | 316222cbcd698f6236fcceadb16d3d1e491e8c04 (patch) | |
| tree | 6426a314340bc0c58206740fecf5851e0dab7e56 | |
| parent | ce111536994e37f470fbe5dc4c425baaffe87057 (diff) | |
| download | ltp-316222cbcd698f6236fcceadb16d3d1e491e8c04.tar.gz | |
clock_gettime01: avoid zero exec runtime due to irq and steal time accountingandroid13-tests-dev
Test is sporadically failing on KVM guests with zero-ed timespec
returned by CLOCK_{PROCESS,THREAD}_CPUTIME_ID. This can be reproduced
on kernels v4.18 and v5.13-rc3 which have IRQ and PARAVIRT TIME
ACCOUNTING enabled.
Task exectime is usually updated on call of clock_gettime().
But update_rq_clock_task() may not update clock_task if there's
more unaccounted irq or steal time than rq->clock delta since
last call. In this instance rq->clock_task does not advance
and it is left for next update to account rest. Because LTP
test is quick and checks only once, it sometimes sees zero
timespec and treats it as failure.
Add a small warm-up to setup() in form of busy loop, to make
sure that clock_task advanced. In case of bug we would either
hit a timeout or still report zeroed timespec.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
(cherry picked from commit 783164765c77cb1180e285e495e51eb60186ece5)
Bug: 193878093
Test: atest -a vts_ltp_test_x86_64:syscalls.clock_gettime01_64bit
Change-Id: Iebfe4e42d46ea62f9bdfb699cf82ee2355c5fd60
Merged-In: Iecd9f56d8980a8fe0db7d70f2a276de5a2503908
Signed-off-by: Edward Liaw <edliaw@google.com>
| -rw-r--r-- | testcases/kernel/syscalls/clock_gettime/clock_gettime01.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/testcases/kernel/syscalls/clock_gettime/clock_gettime01.c b/testcases/kernel/syscalls/clock_gettime/clock_gettime01.c index be9573afc..11da39cf0 100644 --- a/testcases/kernel/syscalls/clock_gettime/clock_gettime01.c +++ b/testcases/kernel/syscalls/clock_gettime/clock_gettime01.c @@ -73,7 +73,15 @@ static struct time64_variants variants[] = { static void setup(void) { + long unsigned utime; + tst_res(TINFO, "Testing variant: %s", variants[tst_variant].desc); + + do { + SAFE_FILE_SCANF("/proc/self/stat", + "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %lu", + &utime); + } while (utime == 0); } static void verify_clock_gettime(unsigned int i) @@ -118,4 +126,5 @@ static struct tst_test test = { .test_variants = ARRAY_SIZE(variants), .setup = setup, .needs_root = 1, + .timeout = 10, }; |