Benjamin Gray <bg...@linux.ibm.com> writes:
> Add new cases to the relevant tests that use explicitly synchronized
> threads to test the behaviour across context switches with less
> randomness. By locking the participants to the same CPU we guarantee a
> context switch occurs each time they make progress, which is a likely
> failure point if the kernel is not tracking the thread local DSCR
> correctly.
>
> The random case is left in to keep exercising potential edge cases.
>
> Signed-off-by: Benjamin Gray <bg...@linux.ibm.com>
> ---
> tools/testing/selftests/powerpc/dscr/Makefile | 1 +
> tools/testing/selftests/powerpc/dscr/dscr.h | 23 +++++
> .../powerpc/dscr/dscr_default_test.c | 87 ++++++++++++++++---
> .../powerpc/dscr/dscr_explicit_test.c | 87 ++++++++++++++++++-
> 4 files changed, 183 insertions(+), 15 deletions(-)
...
> diff --git a/tools/testing/selftests/powerpc/dscr/dscr.h
> b/tools/testing/selftests/powerpc/dscr/dscr.h
> index 2c54998d4715..903ee0c83fac 100644
> --- a/tools/testing/selftests/powerpc/dscr/dscr.h
> +++ b/tools/testing/selftests/powerpc/dscr/dscr.h
> @@ -90,4 +92,25 @@ double uniform_deviate(int seed)
> {
> return seed * (1.0 / (RAND_MAX + 1.0));
> }
> +
> +int restrict_to_one_cpu(void)
> +{
> + cpu_set_t cpus;
> + int cpu;
> +
> + FAIL_IF(sched_getaffinity(0, sizeof(cpu_set_t), &cpus));
> +
> + for (cpu = 0; cpu < CPU_SETSIZE; cpu++)
> + if (CPU_ISSET(cpu, &cpus))
> + break;
> +
> + FAIL_IF(cpu == CPU_SETSIZE);
> +
> + CPU_ZERO(&cpus);
> + CPU_SET(cpu, &cpus);
> + FAIL_IF(sched_setaffinity(0, sizeof(cpu_set_t), &cpus));
> +
> + return 0;
> +}
We have pick_online_cpu() in utils.c, can you use that?
You probably also need to move bind_to_cpu() from pmu/lib.c to utils.c
so you can use it.
cheers
