gem_wsim: Minimize startup gap

Do the GPU quiesce as close as possible in time to the start of
the workload in order to minimize the gap in engine utilization
tracking.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
index a3eb56d0..58a428ab 100644
--- a/benchmarks/gem_wsim.c
+++ b/benchmarks/gem_wsim.c
@@ -1579,7 +1579,15 @@ int main(int argc, char **argv)
 	double t;
 	int i, c;
 
-	fd = drm_open_driver(DRIVER_INTEL);
+	/*
+	 * Open the device via the low-level API so we can do the GPU quiesce
+	 * manually as close as possible in time to the start of the workload.
+	 * This minimizes the gap in engine utilization tracking when observed
+	 * via external tools like trace.pl.
+	 */
+	fd = __drm_open_driver(DRIVER_INTEL);
+	igt_require(fd);
+
 	init_clocks();
 
 	while ((c = getopt(argc, argv, "hqv2RSHxc:n:r:w:W:t:b:")) != -1) {
@@ -1745,6 +1753,8 @@ int main(int argc, char **argv)
 		prepare_workload(i, w[i], flags_);
 	}
 
+	gem_quiescent_gpu(fd);
+
 	clock_gettime(CLOCK_MONOTONIC, &t_start);
 
 	igt_fork(child, clients) {