From ffba1cec3cb4a4bf53bba1e333e3ac94c52ce8a2 Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Wed, 7 Mar 2018 11:08:12 +0000 Subject: tests/perf_pmu: Use absolute tolerance in accuracy tests We need to use absolute tolerance when asserting on percentages. Relative tolerance in this case is unfair and inaccurate since it's strictness varies with relative target busyness. v2: * Do not include spin batch edit and submit into measured time. * Open PMU before child is in test PWM phase. * No need to emit test PWM for twice as long with the new explicit synchroniazation via pipe. * Log test duration in ms for better readability. * Drop inverse assert. (Chris Wilson) v3: Explain tasklet delay. (Chris Wilson) Signed-off-by: Tvrtko Ursulin Cc: Chris Wilson Reviewed-by: Chris Wilson --- tests/perf_pmu.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-) (limited to 'tests/perf_pmu.c') diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c index 9ebffc64..19fcc95f 100644 --- a/tests/perf_pmu.c +++ b/tests/perf_pmu.c @@ -1459,7 +1459,15 @@ static void __rearm_spin_batch(igt_spin_t *spin) __sync_synchronize(); } -#define div_round_up(a, b) (((a) + (b) - 1) / (b)) +#define __assert_within(x, ref, tol_up, tol_down) \ + igt_assert_f((double)(x) <= ((double)(ref) + (tol_up)) && \ + (double)(x) >= ((double)(ref) - (tol_down)), \ + "%f not within +%f/-%f of %f! ('%s' vs '%s')\n", \ + (double)(x), (double)(tol_up), (double)(tol_down), \ + (double)(ref), #x, #ref) + +#define assert_within(x, ref, tolerance) \ + __assert_within(x, ref, tolerance, tolerance) static void accuracy(int gem_fd, const struct intel_execution_engine2 *e, @@ -1493,8 +1501,8 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, while (test_us < min_test_us) test_us += busy_us + idle_us; - igt_info("calibration=%luus, test=%luus; ratio=%.2f%% (%luus/%luus)\n", - pwm_calibration_us, test_us, + igt_info("calibration=%lums, test=%lums; ratio=%.2f%% (%luus/%luus)\n", + pwm_calibration_us / 1000, test_us / 1000, (double)busy_us / (busy_us + idle_us) * 100.0, busy_us, idle_us); @@ -1507,7 +1515,7 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, igt_fork(child, 1) { struct sched_param rt = { .sched_priority = 99 }; const unsigned long timeout[] = { - pwm_calibration_us * 1000, test_us * 2 * 1000 + pwm_calibration_us * 1000, test_us * 1000 }; struct drm_i915_gem_exec_object2 obj = {}; uint64_t total_busy_ns = 0, total_idle_ns = 0; @@ -1537,19 +1545,23 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, igt_nsec_elapsed(&test_start); do { - struct timespec t_busy = { }; - unsigned int target_idle_us; - - igt_nsec_elapsed(&t_busy); + unsigned int target_idle_us, t_busy; /* Restart the spinbatch. */ __rearm_spin_batch(spin); __submit_spin_batch(gem_fd, &obj, e); - measured_usleep(busy_us); + + /* + * Note that the submission may be delayed to a + * tasklet (ksoftirqd) which cannot run until we + * sleep as we hog the cpu (we are RT). + */ + + t_busy = measured_usleep(busy_us); igt_spin_batch_end(spin); gem_sync(gem_fd, obj.handle); - total_busy_ns += igt_nsec_elapsed(&t_busy); + total_busy_ns += t_busy; target_idle_us = (100 * total_busy_ns / target_busy_pct - (total_busy_ns + total_idle_ns)) / 1000; @@ -1569,12 +1581,13 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, igt_spin_batch_free(gem_fd, spin); } + fd = open_pmu(I915_PMU_ENGINE_BUSY(e->class, e->instance)); + /* Let the child run. */ read(link[0], &expected, sizeof(expected)); - assert_within_epsilon(expected, target_busy_pct/100., 0.05); + assert_within(100.0 * expected, target_busy_pct, 5); /* Collect engine busyness for an interesting part of child runtime. */ - fd = open_pmu(I915_PMU_ENGINE_BUSY(e->class, e->instance)); val[0] = __pmu_read_single(fd, &ts[0]); read(link[0], &expected, sizeof(expected)); val[1] = __pmu_read_single(fd, &ts[1]); @@ -1590,8 +1603,7 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, igt_info("error=%.2f%% (%.2f%% vs %.2f%%)\n", __error(busy_r, expected), 100 * busy_r, 100 * expected); - assert_within_epsilon(busy_r, expected, 0.15); - assert_within_epsilon(1 - busy_r, 1 - expected, 0.15); + assert_within(100.0 * busy_r, 100.0 * expected, 2); } igt_main -- cgit v1.2.3