Re: [PATCH v5 09/14] drm/syncobj: Add deadline support for syncobj waits

[Pekka Paalanen]

On Mon, 20 Feb 2023 12:18:56 -0800
Rob Clark <robdclark@xxxxxxxxx> wrote:

> From: Rob Clark <robdclark@xxxxxxxxxxxx>
> 
> Add a new flag to let userspace provide a deadline as a hint for syncobj
> and timeline waits.  This gives a hint to the driver signaling the
> backing fences about how soon userspace needs it to compete work, so it
> can addjust GPU frequency accordingly.  An immediate deadline can be
> given to provide something equivalent to i915 "wait boost".
> 
> v2: Use absolute u64 ns value for deadline hint, drop cap and driver
>     feature flag in favor of allowing count_handles==0 as a way for
>     userspace to probe kernel for support of new flag
> 
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_syncobj.c | 59 +++++++++++++++++++++++++++--------
>  include/uapi/drm/drm.h        |  5 +++
>  2 files changed, 51 insertions(+), 13 deletions(-)

...

> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 642808520d92..aefc8cc743e0 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -887,6 +887,7 @@ struct drm_syncobj_transfer {
>  #define DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL (1 << 0)
>  #define DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT (1 << 1)
>  #define DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE (1 << 2) /* wait for time point to become available */
> +#define DRM_SYNCOBJ_WAIT_FLAGS_WAIT_DEADLINE (1 << 3) /* set fence deadline based to deadline_nsec/sec */

Hi,

where is the UAPI documentation explaining what is a "fence deadline"
and what setting it does here?

btw. no nsec/sec anymore.


Thanks,
pq


>  struct drm_syncobj_wait {
>  	__u64 handles;
>  	/* absolute timeout */
> @@ -895,6 +896,8 @@ struct drm_syncobj_wait {
>  	__u32 flags;
>  	__u32 first_signaled; /* only valid when not waiting all */
>  	__u32 pad;
> +	/* Deadline hint to set on backing fence(s) in CLOCK_MONOTONIC: */
> +	__u64 deadline_ns;
>  };
>  
>  struct drm_syncobj_timeline_wait {
> @@ -907,6 +910,8 @@ struct drm_syncobj_timeline_wait {
>  	__u32 flags;
>  	__u32 first_signaled; /* only valid when not waiting all */
>  	__u32 pad;
> +	/* Deadline hint to set on backing fence(s) in CLOCK_MONOTONIC: */
> +	__u64 deadline_ns;
>  };
>  
>

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