As Daniel commented on
commit b7ffe1362c5f468b853223acc9268804aa92afc8
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Mon Apr 27 13:41:24 2015 +0100
drm/i915: Free RPS boosts for all laggards
it is better to be explicit when sharing hardcoded values such as
throttle/boost timeouts. Make it so!
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 6 ++++++
drivers/gpu/drm/i915/i915_gem.c | 2 +-
drivers/gpu/drm/i915/intel_pm.c | 2 +-
3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index abd0914b4849..30ffb9138116 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -279,6 +279,12 @@ struct drm_i915_file_private {
struct {
spinlock_t lock;
struct list_head request_list;
+/* 20ms is a fairly arbitrary limit (greater than the average frame time)
+ * chosen to prevent the CPU getting more than a frame ahead of the GPU
+ * (when using lax throttling for the frontbuffer). We also use it to
+ * offer free GPU waitboosts for severely congested workloads.
+ */
+#define DRM_I915_THROTTLE_JIFFIES msecs_to_jiffies(20)
} mm;
struct idr context_idr;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index ca41fc56f246..9ae98b00ff56 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4211,7 +4211,7 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_file_private *file_priv = file->driver_priv;
- unsigned long recent_enough = jiffies - msecs_to_jiffies(20);
+ unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
struct drm_i915_gem_request *request, *target = NULL;
unsigned reset_counter;
int ret;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 833f9dd28fea..abeb7fca17c8 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4164,7 +4164,7 @@ void gen6_rps_boost(struct drm_i915_private *dev_priv,
/* Force a RPS boost (and don't count it against the client) if
* the GPU is severely congested.
*/
- if (rps && time_after(jiffies, submitted + msecs_to_jiffies(20)))
+ if (rps && time_after(jiffies, submitted + DRM_I915_THROTTLE_JIFFIES))
rps = NULL;
spin_lock(&dev_priv->rps.client_lock);
--
2.1.4
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
