[PATCH libdrm] amdgpu: Add context priority override function.

[Bas Nieuwenhuizen]

On Wed, Apr 17, 2019 at 9:21 PM Andres Rodriguez <andresx7 at gmail.com> wrote:
>
>
>
> On 2019-04-17 2:33 p.m., Bas Nieuwenhuizen wrote:
> > This way we can override the priority of a single context using a
> > master fd.
> >
> > Since we cannot usefully create an amdgpu device of a master fd
> > without the fd deduplication kicking in this takes a plain fd.
> >
> > This can be used by e.g. radv to get high priority contexts using
> > a master fd from the primary node or a lease
> > ---
> >   amdgpu/amdgpu-symbol-check |  1 +
> >   amdgpu/amdgpu.h            | 15 +++++++++++++++
> >   amdgpu/amdgpu_cs.c         | 25 +++++++++++++++++++++++++
> >   3 files changed, 41 insertions(+)
> >
> > diff --git a/amdgpu/amdgpu-symbol-check b/amdgpu/amdgpu-symbol-check
> > index 96a44b40..4d806922 100755
> > --- a/amdgpu/amdgpu-symbol-check
> > +++ b/amdgpu/amdgpu-symbol-check
> > @@ -38,6 +38,7 @@ amdgpu_cs_create_syncobj2
> >   amdgpu_cs_ctx_create
> >   amdgpu_cs_ctx_create2
> >   amdgpu_cs_ctx_free
> > +amdgpu_cs_ctx_override_priority
> >   amdgpu_cs_destroy_semaphore
> >   amdgpu_cs_destroy_syncobj
> >   amdgpu_cs_export_syncobj
> > diff --git a/amdgpu/amdgpu.h b/amdgpu/amdgpu.h
> > index d6de3b8d..3d838e08 100644
> > --- a/amdgpu/amdgpu.h
> > +++ b/amdgpu/amdgpu.h
> > @@ -911,6 +911,21 @@ int amdgpu_cs_ctx_create(amdgpu_device_handle dev,
> >   */
> >   int amdgpu_cs_ctx_free(amdgpu_context_handle context);
> >
> > +/**
> > + * Override the submission priority for the given context using a master fd.
> > + *
> > + * \param   dev             - \c [in] device handle
>
> Minor indentation misalignment here.

Fixed locally.
>
> > + * \param   context    - \c [in] context handle for context id
> > + * \param   master_fd  - \c [in] The master fd to authorize the override.
> > + * \param   priority   - \c [in] The priority to assign to the context.
> > + *
> > + * \return 0 on success or a a negative Posix error code on failure.
> > + */
> > +int amdgpu_cs_ctx_override_priority(amdgpu_device_handle dev,
> > +                                    amdgpu_context_handle context,
> > +                                    int master_fd,
> > +                                    unsigned priority);
> > +
> >   /**
> >    * Query reset state for the specific GPU Context
> >    *
> > diff --git a/amdgpu/amdgpu_cs.c b/amdgpu/amdgpu_cs.c
> > index 5bedf748..7ee844fb 100644
> > --- a/amdgpu/amdgpu_cs.c
> > +++ b/amdgpu/amdgpu_cs.c
> > @@ -142,6 +142,31 @@ drm_public int amdgpu_cs_ctx_free(amdgpu_context_handle context)
> >       return r;
> >   }
> >
> > +drm_public int amdgpu_cs_ctx_override_priority(amdgpu_device_handle dev,
> > +                                               amdgpu_context_handle context,
> > +                                               int master_fd,
> > +                                               unsigned priority)
> > +{
> > +     int r;
> > +
> > +     if (!dev || !context || master_fd < 0)
> > +             return -EINVAL;
> > +
> > +     union drm_amdgpu_sched args;
> > +     memset(&args, 0, sizeof(args));
> > +
> > +     args.in.op = AMDGPU_SCHED_OP_CONTEXT_PRIORITY_OVERRIDE;
> > +     args.in.fd = dev->fd;
> > +     args.in.priority = priority;
> > +     args.in.ctx_id = context->id;
> > +
> > +     r = drmCommandWrite(master_fd, DRM_AMDGPU_SCHED, &args, sizeof(args));
>
> I'm assuming there is no other initialization required before this
> command can be executed on the master_fd.

Correct. The two limitations are (1) master_fd should be an amdgpu fd
(as we call the ioctl on master fd) and (2) master_fd should be
allowed to do ioctls guarded with DRM_MASTER. Neither requires any
extra initialization.

>
> If so, this changed is:
> Reviewed-by: Andres Rodriguez <andresx7 at gmail.com>

Thanks!

>
>
> > +     if (r)
> > +             return r;
> > +
> > +     return 0;
> > +}
> > +
> >   drm_public int amdgpu_cs_query_reset_state(amdgpu_context_handle context,
> >                                          uint32_t *state, uint32_t *hangs)
> >   {
> >