On Tue, 21 Feb 2023 09:25:18 -0800
Rob Clark <robdclark@xxxxxxxxx> wrote:
> On Tue, Feb 21, 2023 at 12:53 AM Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote:
> >
> > 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?
>
> It's with the rest of the drm_syncobj UAPI docs ;-)
Is that https://www.kernel.org/doc/html/latest/driver-api/dma-buf.html#dma-fence-uabi-sync-file ?
That whole page never mentions e.g. WAIT_AVAILABLE, so at least the
flags are not there. Does not mention syncobj_wait either.
I could ask where the real non-IGT userspace is or the plan for it,
too, since this is new DRM UAPI.
Thanks,
pq
>
> BR,
> -R
>
> > 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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