In order to test how fast the heartbeat can respond, we measure with the interval set to its minimum. Before we measure though, we want to be sure we start with a fresh pulse, and so wait until any old one is complete. During that wait though, we were continually flushing the work, and so continually re-evaluating to see if the pulse was complete, and each attempt would count as an unresponsive system. If the engine did not complete the request in the couple of busy-spins, it would flag an error. This is unfortunate, so let's not busy-spin waiting for the old heartbeat, but terminate it and start afresh.
Signed-off-by: Chris Wilson <[email protected]> --- drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c index e73854dd2fe0..b88aa35ad75b 100644 --- a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c +++ b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c @@ -215,16 +215,17 @@ static int __live_heartbeat_fast(struct intel_engine_cs *engine) goto err_pm; for (i = 0; i < ARRAY_SIZE(times); i++) { - /* Manufacture a tick */ do { - while (READ_ONCE(engine->heartbeat.systole)) - flush_delayed_work(&engine->heartbeat.work); + /* Manufacture a tick */ + intel_engine_park_heartbeat(engine); + GEM_BUG_ON(engine->heartbeat.systole); + engine->serial++; /* pretend we are not idle! */ + intel_engine_unpark_heartbeat(engine); - engine->serial++; /* quick, pretend we are not idle! */ flush_delayed_work(&engine->heartbeat.work); if (!delayed_work_pending(&engine->heartbeat.work)) { - pr_err("%s: heartbeat did not start\n", - engine->name); + pr_err("%s: heartbeat %d did not start\n", + engine->name, i); err = -EINVAL; goto err_pm; } -- 2.20.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
