[PATCH 062/109] drm/i915: Do not use iowait while waiting for the GPU

Chris Wilson chris at chris-wilson.co.uk
Wed Jan 2 16:47:19 UTC 2019


A recent trend for cpufreq is to boost the CPU frequencies for
iowaiters, in particularly to benefit high frequency I/O. We do the same
and boost the GPU clocks to try and minimise time spent waiting for the
GPU. However, as the igfx and CPU share the same TDP, boosting the CPU
frequency will result in the GPU being throttled and its frequency being
reduced. Thus declaring iowait negatively impacts on GPU throughput.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107410
References: 52ccc4314293 ("cpufreq: intel_pstate: HWP boost performance on IO wakeup")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen at intel.com>
Cc: Francisco Jerez <currojerez at riseup.net>
---
 drivers/gpu/drm/i915/i915_request.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index d1c55427b8f7..f5d9f947d3ba 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1131,7 +1131,7 @@ long i915_request_wait(struct i915_request *rq,
 			break;
 		}
 
-		timeout = io_schedule_timeout(timeout);
+		timeout = schedule_timeout(timeout);
 	}
 	__set_current_state(TASK_RUNNING);
 
-- 
2.20.1



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