diff mbox

[1/2] drm/i915: Align the hangcheck wakeup to the nearest second

Message ID 1349445188-16253-1-git-send-email-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Chris Wilson Oct. 5, 2012, 1:53 p.m. UTC
round_jiffies() aligns the wakeup time to the nearest second in order to
batch wakeups and reduce system load, which is useful for unimportant
coarse timers like our hangcheck.

Suggested-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_gem.c |    3 +--
 drivers/gpu/drm/i915/i915_irq.c |    5 ++---
 3 files changed, 4 insertions(+), 5 deletions(-)

Comments

Jani Nikula Oct. 5, 2012, 3:40 p.m. UTC | #1
On Fri, 05 Oct 2012, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> round_jiffies() aligns the wakeup time to the nearest second in order to
> batch wakeups and reduce system load, which is useful for unimportant
> coarse timers like our hangcheck.
>
> Suggested-by: Arjan van de Ven <arjan@linux.intel.com>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Arjan van de Ven <arjan@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    1 +
>  drivers/gpu/drm/i915/i915_gem.c |    3 +--
>  drivers/gpu/drm/i915/i915_irq.c |    5 ++---
>  3 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d8043af..f79c664 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -460,6 +460,7 @@ typedef struct drm_i915_private {
>  
>  	/* For hangcheck timer */
>  #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
> +#define DRM_I915_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD)
>  	struct timer_list hangcheck_timer;
>  	int hangcheck_count;
>  	uint32_t last_acthd[I915_NUM_RINGS];
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index c78f8e3..8e05d53 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2151,8 +2151,7 @@ i915_add_request(struct intel_ring_buffer *ring,
>  	if (!dev_priv->mm.suspended) {
>  		if (i915_enable_hangcheck) {
>  			mod_timer(&dev_priv->hangcheck_timer,
> -				  jiffies +
> -				  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
> +				  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));

What is DRM_I915_HANGCHECK_PERIOD based on; specifically is it a strict
minimum value? Should round_jiffies_*up*_relative() be used instead?

BR,
Jani.


>  		}
>  		if (was_empty) {
>  			queue_delayed_work(dev_priv->wq,
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index e18e56b..67dc487 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -353,8 +353,7 @@ static void notify_ring(struct drm_device *dev,
>  	if (i915_enable_hangcheck) {
>  		dev_priv->hangcheck_count = 0;
>  		mod_timer(&dev_priv->hangcheck_timer,
> -			  jiffies +
> -			  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
> +			  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
>  	}
>  }
>  
> @@ -1787,7 +1786,7 @@ void i915_hangcheck_elapsed(unsigned long data)
>  repeat:
>  	/* Reset timer case chip hangs without another request being added */
>  	mod_timer(&dev_priv->hangcheck_timer,
> -		  jiffies + msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
> +		  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
>  }
>  
>  /* drm_dma.h hooks
> -- 
> 1.7.10.4
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Chris Wilson Oct. 5, 2012, 3:51 p.m. UTC | #2
On Fri, 05 Oct 2012 18:40:05 +0300, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Fri, 05 Oct 2012, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> > round_jiffies() aligns the wakeup time to the nearest second in order to
> > batch wakeups and reduce system load, which is useful for unimportant
> > coarse timers like our hangcheck.
> >
> > Suggested-by: Arjan van de Ven <arjan@linux.intel.com>
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Arjan van de Ven <arjan@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h |    1 +
> >  drivers/gpu/drm/i915/i915_gem.c |    3 +--
> >  drivers/gpu/drm/i915/i915_irq.c |    5 ++---
> >  3 files changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index d8043af..f79c664 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -460,6 +460,7 @@ typedef struct drm_i915_private {
> >  
> >  	/* For hangcheck timer */
> >  #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
> > +#define DRM_I915_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD)
> >  	struct timer_list hangcheck_timer;
> >  	int hangcheck_count;
> >  	uint32_t last_acthd[I915_NUM_RINGS];
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index c78f8e3..8e05d53 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -2151,8 +2151,7 @@ i915_add_request(struct intel_ring_buffer *ring,
> >  	if (!dev_priv->mm.suspended) {
> >  		if (i915_enable_hangcheck) {
> >  			mod_timer(&dev_priv->hangcheck_timer,
> > -				  jiffies +
> > -				  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
> > +				  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
> 
> What is DRM_I915_HANGCHECK_PERIOD based on; specifically is it a strict
> minimum value? Should round_jiffies_*up*_relative() be used instead?

It's a random value plucked out of the air for being long enough that
any typical batch will have completed and short enough that the user
doesn't turn the machine off in digust. Typically we repeat the
hangcheck as well to confirm that GPU is dead before starting the error
recovery. Rounding up is slightly preferable.
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8043af..f79c664 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -460,6 +460,7 @@  typedef struct drm_i915_private {
 
 	/* For hangcheck timer */
 #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
+#define DRM_I915_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD)
 	struct timer_list hangcheck_timer;
 	int hangcheck_count;
 	uint32_t last_acthd[I915_NUM_RINGS];
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c78f8e3..8e05d53 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2151,8 +2151,7 @@  i915_add_request(struct intel_ring_buffer *ring,
 	if (!dev_priv->mm.suspended) {
 		if (i915_enable_hangcheck) {
 			mod_timer(&dev_priv->hangcheck_timer,
-				  jiffies +
-				  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+				  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 		}
 		if (was_empty) {
 			queue_delayed_work(dev_priv->wq,
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e18e56b..67dc487 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -353,8 +353,7 @@  static void notify_ring(struct drm_device *dev,
 	if (i915_enable_hangcheck) {
 		dev_priv->hangcheck_count = 0;
 		mod_timer(&dev_priv->hangcheck_timer,
-			  jiffies +
-			  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+			  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 	}
 }
 
@@ -1787,7 +1786,7 @@  void i915_hangcheck_elapsed(unsigned long data)
 repeat:
 	/* Reset timer case chip hangs without another request being added */
 	mod_timer(&dev_priv->hangcheck_timer,
-		  jiffies + msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+		  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 }
 
 /* drm_dma.h hooks