diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2018-08-08 14:20:26 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2018-08-31 14:46:56 +0100 |
| commit | 1754cbd35005605a80b06d808b4f891555a151cd (patch) | |
| tree | 282a8e1b970f5692f4441a5cce1724e35f9a63cb /tests/perf_pmu.c | |
| parent | 46c35f25d777f7992d87ea44f038035a6eaec2c2 (diff) | |
igt/perf_pmu: Aim for a fixed number of iterations for calibrating accuracy
Our observation is that the systematic error is proportional to the
number of iterations we perform; the suspicion is that it directly
correlates with the number of sleeps. Reduce the number of iterations,
to try and keep the error in check.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Diffstat (limited to 'tests/perf_pmu.c')
| -rw-r--r-- | tests/perf_pmu.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c index 9a20abb6..5a26d527 100644 --- a/tests/perf_pmu.c +++ b/tests/perf_pmu.c @@ -1521,14 +1521,13 @@ static void __rearm_spin_batch(igt_spin_t *spin) static void accuracy(int gem_fd, const struct intel_execution_engine2 *e, - unsigned long target_busy_pct) + unsigned long target_busy_pct, + unsigned long target_iters) { - unsigned long busy_us = 10000 - 100 * (1 + abs(50 - target_busy_pct)); - unsigned long idle_us = 100 * (busy_us - target_busy_pct * - busy_us / 100) / target_busy_pct; const unsigned long min_test_us = 1e6; - const unsigned long pwm_calibration_us = min_test_us; - const unsigned long test_us = min_test_us; + unsigned long pwm_calibration_us; + unsigned long test_us; + unsigned long cycle_us, busy_us, idle_us; double busy_r, expected; uint64_t val[2]; uint64_t ts[2]; @@ -1538,18 +1537,27 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e, /* Sampling platforms cannot reach the high accuracy criteria. */ igt_require(gem_has_execlists(gem_fd)); - while (idle_us < 2500) { + /* Aim for approximately 100 iterations for calibration */ + cycle_us = min_test_us / target_iters; + busy_us = cycle_us * target_busy_pct / 100; + idle_us = cycle_us - busy_us; + + while (idle_us < 2500 || busy_us < 2500) { busy_us *= 2; idle_us *= 2; } + cycle_us = busy_us + idle_us; + pwm_calibration_us = target_iters * cycle_us / 2; + test_us = target_iters * cycle_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, + igt_info("calibration=%lums, test=%lums, cycle=%lums; ratio=%.2f%% (%luus/%luus)\n", + pwm_calibration_us / 1000, test_us / 1000, cycle_us / 1000, + (double)busy_us / cycle_us * 100.0, busy_us, idle_us); - assert_within_epsilon((double)busy_us / (busy_us + idle_us), - (double)target_busy_pct / 100.0, tolerance); + assert_within_epsilon((double)busy_us / cycle_us, + (double)target_busy_pct / 100.0, + tolerance); igt_assert(pipe(link) == 0); @@ -1796,7 +1804,7 @@ igt_main for (i = 0; i < ARRAY_SIZE(pct); i++) { igt_subtest_f("busy-accuracy-%u-%s", pct[i], e->name) - accuracy(fd, e, pct[i]); + accuracy(fd, e, pct[i], 10); } igt_subtest_f("busy-hang-%s", e->name) |