mbox series

[v4,00/14] dma-fence: Deadline awareness

Message ID 20230218211608.1630586-1-robdclark@gmail.com
Headers
Series dma-fence: Deadline awareness |

Message

Rob Clark Feb. 18, 2023, 9:15 p.m. UTC 
  From: Rob Clark <robdclark@chromium.org>

This series adds deadline awareness to fences, so realtime deadlines
such as vblank can be communicated to the fence signaller for power/
frequency management decisions.

This is partially inspired by a trick i915 does, but implemented
via dma-fence for a couple of reasons:

1) To continue to be able to use the atomic helpers
2) To support cases where display and gpu are different drivers

This iteration adds a dma-fence ioctl to set a deadline (both to
support igt-tests, and compositors which delay decisions about which
client buffer to display), and a sw_sync ioctl to read back the
deadline.  IGT tests utilizing these can be found at:

  https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline


v1: https://patchwork.freedesktop.org/series/93035/
v2: Move filtering out of later deadlines to fence implementation
    to avoid increasing the size of dma_fence
v3: Add support in fence-array and fence-chain; Add some uabi to
    support igt tests and userspace compositors.
v4: Rebase, address various comments, and add syncobj deadline
    support, and sync_file EPOLLPRI based on experience with perf/
    freq issues with clvk compute workloads on i915 (anv)

Rob Clark (14):
  dma-buf/dma-fence: Add deadline awareness
  dma-buf/fence-array: Add fence deadline support
  dma-buf/fence-chain: Add fence deadline support
  dma-buf/dma-resv: Add a way to set fence deadline
  dma-buf/sync_file: Add SET_DEADLINE ioctl
  dma-buf/sync_file: Support (E)POLLPRI
  dma-buf/sw_sync: Add fence deadline support
  drm/scheduler: Add fence deadline support
  drm/syncobj: Add deadline support for syncobj waits
  drm/vblank: Add helper to get next vblank time
  drm/atomic-helper: Set fence deadline for vblank
  drm/msm: Add deadline based boost support
  drm/msm: Add wait-boost support
  drm/i915: Add deadline based boost support

 drivers/dma-buf/dma-fence-array.c       | 11 ++++
 drivers/dma-buf/dma-fence-chain.c       | 13 +++++
 drivers/dma-buf/dma-fence.c             | 20 +++++++
 drivers/dma-buf/dma-resv.c              | 19 +++++++
 drivers/dma-buf/sw_sync.c               | 58 +++++++++++++++++++
 drivers/dma-buf/sync_debug.h            |  2 +
 drivers/dma-buf/sync_file.c             | 27 +++++++++
 drivers/gpu/drm/drm_atomic_helper.c     | 36 ++++++++++++
 drivers/gpu/drm/drm_ioctl.c             |  3 +
 drivers/gpu/drm/drm_syncobj.c           | 59 ++++++++++++++++----
 drivers/gpu/drm/drm_vblank.c            | 32 +++++++++++
 drivers/gpu/drm/i915/i915_driver.c      |  2 +-
 drivers/gpu/drm/i915/i915_request.c     | 20 +++++++
 drivers/gpu/drm/msm/msm_drv.c           | 16 ++++--
 drivers/gpu/drm/msm/msm_fence.c         | 74 +++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_fence.h         | 20 +++++++
 drivers/gpu/drm/msm/msm_gem.c           |  5 ++
 drivers/gpu/drm/scheduler/sched_fence.c | 46 +++++++++++++++
 drivers/gpu/drm/scheduler/sched_main.c  |  2 +-
 include/drm/drm_drv.h                   |  6 ++
 include/drm/drm_vblank.h                |  1 +
 include/drm/gpu_scheduler.h             |  8 +++
 include/linux/dma-fence.h               | 20 +++++++
 include/linux/dma-resv.h                |  2 +
 include/uapi/drm/drm.h                  | 16 +++++-
 include/uapi/drm/msm_drm.h              | 14 ++++-
 include/uapi/linux/sync_file.h          | 22 ++++++++
 27 files changed, 532 insertions(+), 22 deletions(-)

Comments

Tvrtko Ursulin Feb. 20, 2023, 3:46 p.m. UTC | #1 
On 18/02/2023 21:15, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> 
> This should probably be re-written by someone who knows the i915
> request/timeline stuff better, to deal with non-immediate deadlines.
> But as-is I think this should be enough to handle the case where
> we want syncobj waits to trigger boost.

Yeah, there are endless possibilities. :) But I think it is effectively 
similar enough to current waitboosting (when waits are done using the 
i915 specific ioctl). So as a first step I'll try to organize some 
internal power and performance testing, at least Chromebook focused, to 
see if modern userspace (syncobj based) even benefits and does not by 
some chance regress over the board.

Regards,

Tvrtko

> 
>   drivers/gpu/drm/i915/i915_driver.c  |  2 +-
>   drivers/gpu/drm/i915/i915_request.c | 20 ++++++++++++++++++++
>   2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index cf1c0970ecb4..bd40b7bcb38a 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -1781,7 +1781,7 @@ static const struct drm_driver i915_drm_driver = {
>   	.driver_features =
>   	    DRIVER_GEM |
>   	    DRIVER_RENDER | DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_SYNCOBJ |
> -	    DRIVER_SYNCOBJ_TIMELINE,
> +	    DRIVER_SYNCOBJ_TIMELINE | DRIVER_SYNCOBJ_DEADLINE,
>   	.release = i915_driver_release,
>   	.open = i915_driver_open,
>   	.lastclose = i915_driver_lastclose,
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 7503dcb9043b..44491e7e214c 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -97,6 +97,25 @@ static bool i915_fence_enable_signaling(struct dma_fence *fence)
>   	return i915_request_enable_breadcrumb(to_request(fence));
>   }
>   
> +static void i915_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
> +{
> +	struct i915_request *rq = to_request(fence);
> +
> +	if (i915_request_completed(rq))
> +		return;
> +
> +	if (i915_request_started(rq))
> +		return;
> +
> +	/*
> +	 * TODO something more clever for deadlines that are in the
> +	 * future.  I think probably track the nearest deadline in
> +	 * rq->timeline and set timer to trigger boost accordingly?
> +	 */
> +
> +	intel_rps_boost(rq);
> +}
> +
>   static signed long i915_fence_wait(struct dma_fence *fence,
>   				   bool interruptible,
>   				   signed long timeout)
> @@ -182,6 +201,7 @@ const struct dma_fence_ops i915_fence_ops = {
>   	.signaled = i915_fence_signaled,
>   	.wait = i915_fence_wait,
>   	.release = i915_fence_release,
> +	.set_deadline = i915_fence_set_deadline,
>   };
>   
>   static void irq_execute_cb(struct irq_work *wrk)