[Intel-gfx] [PATCH 8/8] drm/i915: Expose RPCS (SSEU) configuration to userspace

[Tvrtko Ursulin]

On 08/05/2018 05:04, Rogozhkin, Dmitry V wrote:
>>>  I'm pretty sure Dmitry wants dynamic configurations.
> 
> Yes, I afraid we really need dynamic slice configurations for media.

Context of the question was whether you need to change slice 
configuration for a single GEM context between submitting batch buffers?

Regards,

Tvrtko


> *From:*Landwerlin, Lionel G
> *Sent:* Friday, May 4, 2018 9:25 AM
> *To:* Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>; 
> intel-gfx at lists.freedesktop.org; Rogozhkin, Dmitry V 
> <dmitry.v.rogozhkin at intel.com>
> *Subject:* Re: [Intel-gfx] [PATCH 8/8] drm/i915: Expose RPCS (SSEU) 
> configuration to userspace
> 
> On 03/05/18 18:18, Tvrtko Ursulin wrote:
> 
>            +int intel_lr_context_set_sseu(struct i915_gem_context *ctx,
>         +                  struct intel_engine_cs *engine,
>         +                  struct i915_gem_context_sseu *sseu)
>         +{
>         +    struct drm_i915_private *dev_priv = ctx->i915;
>         +    struct intel_context *ce;
>         +    enum intel_engine_id id;
>         +    int ret;
>         +
>         +    lockdep_assert_held(&dev_priv->drm.struct_mutex);
>         +
>         +    if (memcmp(sseu, &ctx->engine[engine->id].sseu,
>         sizeof(*sseu)) == 0)
>         +        return 0;
>         +
>         +    /*
>         +     * We can only program this on render ring.
>         +     */
>         +    ce = &ctx->engine[RCS];
>         +
>         +    if (ce->pin_count) { /* Assume that the context is active! */
>         +        ret = i915_gem_switch_to_kernel_context(dev_priv);
>         +        if (ret)
>         +            return ret;
>         +
>         +        ret = i915_gem_wait_for_idle(dev_priv,
>         +                         I915_WAIT_INTERRUPTIBLE |
>         +                         I915_WAIT_LOCKED);
> 
> 
>     Could we consider the alternative of only allowing this to be
>     configured on context create? That way we would not need to idle the
>     GPU every time userspace decides to fiddle with it. It is
>     unprivileged so quite an easy way for random app to ruin GPU
>     performance for everyone.
> 
>     Regards,
> 
>     Tvrtko
> 
> I'm pretty sure Dmitry wants dynamic configurations.
> 
> Dmitry?
>