[Intel-gfx] [PATCH 2/2] drm/i915: Align the retire_requests worker to the nearest second

[Chris Wilson]

By using round_jiffies() we can align the wakeup of our worker to the
nearest second in order to batch wakeups and reduce system load, which
is useful for unimportant coarse tasks like our retire_requests.

Suggested-by: Arjan van de Ven <arjan at linux.intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Arjan van de Ven <arjan at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 8e05d53..706f481 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2084,6 +2084,11 @@ i915_gem_next_request_seqno(struct intel_ring_buffer *ring)
 	return ring->outstanding_lazy_request;
 }
 
+static unsigned long round_jiffies_delay(unsigned long delay)
+{
+	return round_jiffies_relative(delay) - jiffies;
+}
+
 int
 i915_add_request(struct intel_ring_buffer *ring,
 		 struct drm_file *file,
@@ -2155,7 +2160,8 @@ i915_add_request(struct intel_ring_buffer *ring,
 		}
 		if (was_empty) {
 			queue_delayed_work(dev_priv->wq,
-					   &dev_priv->mm.retire_work, HZ);
+					   &dev_priv->mm.retire_work,
+					   round_jiffies_delay(HZ));
 			intel_mark_busy(dev_priv->dev);
 		}
 	}
@@ -2346,7 +2352,8 @@ i915_gem_retire_work_handler(struct work_struct *work)
 
 	/* Come back later if the device is busy... */
 	if (!mutex_trylock(&dev->struct_mutex)) {
-		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, HZ);
+		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work,
+				   round_jiffies_delay(HZ));
 		return;
 	}
 
@@ -2364,7 +2371,8 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	}
 
 	if (!dev_priv->mm.suspended && !idle)
-		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, HZ);
+		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work,
+				   round_jiffies_delay(HZ));
 	if (idle)
 		intel_mark_idle(dev);
 
-- 
1.7.10.4