[Intel-gfx] [PATCH igt] igt/perf_pmu: Measure the reference batch for busy-check-all

[Chris Wilson]

Don't rely on the timer being precise when we can sleep for a known
duration.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 tests/perf_pmu.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
index e35aca899..1197cae4e 100644
--- a/tests/perf_pmu.c
+++ b/tests/perf_pmu.c
@@ -179,9 +179,12 @@ busy_check_all(int gem_fd, const struct intel_execution_engine2 *e,
 	const struct intel_execution_engine2 *e_;
 	uint64_t val[num_engines];
 	int fd[num_engines];
+	unsigned long slept;
 	igt_spin_t *spin;
 	unsigned int busy_idx, i;
 
+	spin = igt_spin_batch_new(gem_fd, 0, e2ring(gem_fd, e), 0);
+
 	i = 0;
 	fd[0] = -1;
 	for_each_engine_class_instance(fd, e_) {
@@ -197,10 +200,7 @@ busy_check_all(int gem_fd, const struct intel_execution_engine2 *e,
 
 	igt_assert_eq(i, num_engines);
 
-	spin = igt_spin_batch_new(gem_fd, 0, e2ring(gem_fd, e), 0);
-	igt_spin_batch_set_timeout(spin, batch_duration_ns);
-
-	gem_sync(gem_fd, spin->handle);
+	slept = measured_usleep(batch_duration_ns / 1000);
 
 	pmu_read_multi(fd[0], num_engines, val);
 	log_busy(fd[0], num_engines, val);
@@ -208,7 +208,7 @@ busy_check_all(int gem_fd, const struct intel_execution_engine2 *e,
 	igt_spin_batch_free(gem_fd, spin);
 	close(fd[0]);
 
-	assert_within_epsilon(val[busy_idx], batch_duration_ns, tolerance);
+	assert_within_epsilon(val[busy_idx], slept, tolerance);
 	for (i = 0; i < num_engines; i++) {
 		if (i == busy_idx)
 			continue;
-- 
2.15.1