igt/gem_exec_nop: Sync before measuring total elapsed time
The systematic error should be lost in the millions of cycles, but
better pedagogically correct.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/tests/gem_exec_nop.c b/tests/gem_exec_nop.c
index 5a2f1b9..5d0d495 100644
--- a/tests/gem_exec_nop.c
+++ b/tests/gem_exec_nop.c
@@ -387,6 +387,9 @@
count += 1024;
clock_gettime(CLOCK_MONOTONIC, &now);
} while (elapsed(&start, &now) < timeout); /* Hang detection ~120s */
+
+ gem_sync(fd, obj[0].handle);
+ clock_gettime(CLOCK_MONOTONIC, &now);
results[child] = elapsed(&start, &now) / count;
if (flags & CONTEXT)