[igt-dev] [Intel-gfx] [PATCH i-g-t] tests/i915/perf_pmu: Subtest to measure sampling error for 100% busy
Chris Wilson
chris at chris-wilson.co.uk
Tue Feb 16 12:49:33 UTC 2021
Quoting Tvrtko Ursulin (2021-02-16 10:50:50)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Test that periodic reads of engine busyness against a constant 100% load
> are within the 5000ppm tolerance when comparing perf timestamp versus
> counter values.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
> tests/i915/perf_pmu.c | 46 ++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 41 insertions(+), 5 deletions(-)
>
> diff --git a/tests/i915/perf_pmu.c b/tests/i915/perf_pmu.c
> index 50b5c82bc472..728312be5293 100644
> --- a/tests/i915/perf_pmu.c
> +++ b/tests/i915/perf_pmu.c
> @@ -26,6 +26,7 @@
> #include <stdio.h>
> #include <string.h>
> #include <fcntl.h>
> +#include <float.h>
> #include <inttypes.h>
> #include <errno.h>
> #include <signal.h>
> @@ -46,6 +47,7 @@
> #include "igt_perf.h"
> #include "igt_sysfs.h"
> #include "igt_pm.h"
> +#include "igt_stats.h"
> #include "sw_sync.h"
>
> IGT_TEST_DESCRIPTION("Test the i915 pmu perf interface");
> @@ -278,8 +280,11 @@ static void end_spin(int fd, igt_spin_t *spin, unsigned int flags)
> static void
> single(int gem_fd, const struct intel_execution_engine2 *e, unsigned int flags)
> {
> + unsigned int loops = flags & FLAG_LONG ? 20 : 1;
> + double err_min = DBL_MAX, err_max = -DBL_MAX;
> unsigned long slept;
> igt_spin_t *spin;
> + igt_stats_t s;
> uint64_t val;
> int fd;
>
> @@ -290,11 +295,40 @@ single(int gem_fd, const struct intel_execution_engine2 *e, unsigned int flags)
> else
> spin = NULL;
>
> - val = pmu_read_single(fd);
> - slept = measured_usleep(batch_duration_ns / 1000);
> - if (flags & TEST_TRAILING_IDLE)
> - end_spin(gem_fd, spin, flags);
> - val = pmu_read_single(fd) - val;
> + igt_stats_init_with_size(&s, loops);
> +
> + while (--loops) {
while (loops--)
/o\
-Chris
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