On 7 May 2015 15:37, "Chris Wilson" <chris@xxxxxxxxxxxxxxxxxx> wrote:
>
> On Thu, May 07, 2015 at 03:15:50PM +0100, Robert Bragg wrote:
> > +static int init_oa_buffer(struct perf_event *event)
> > +{
> > + struct drm_i915_private *dev_priv =
> > + container_of(event->pmu, typeof(*dev_priv), oa_pmu.pmu);
> > + struct drm_i915_gem_object *bo;
> > + int ret;
> > +
> > + BUG_ON(!IS_HASWELL(dev_priv->dev));
> > + BUG_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
> > + BUG_ON(dev_priv->oa_pmu.oa_buffer.obj);
> > +
> > + spin_lock_init(&dev_priv->oa_pmu.oa_buffer.flush_lock);
> > +
> > + /* NB: We over allocate the OA buffer due to the way raw sample data
> > + * gets copied from the gpu mapped circular buffer into the perf
> > + * circular buffer so that only one copy is required.
> > + *
> > + * For each perf sample (raw->size + 4) needs to be 8 byte aligned,
> > + * where the 4 corresponds to the 32bit raw->size member that's
> > + * added to the sample header that userspace sees.
> > + *
> > + * Due to the + 4 for the size member: when we copy a report to the
> > + * userspace facing perf buffer we always copy an additional 4 bytes
> > + * from the subsequent report to make up for the miss alignment, but
> > + * when a report is at the end of the gpu mapped buffer we need to
> > + * read 4 bytes past the end of the buffer.
> > + */
> > + bo = i915_gem_alloc_object(dev_priv->dev, OA_BUFFER_SIZE + PAGE_SIZE);
> > + if (bo == NULL) {
> > + DRM_ERROR("Failed to allocate OA buffer\n");
> > + ret = -ENOMEM;
> > + goto err;
> > + }
> > + dev_priv->oa_pmu.oa_buffer.obj = bo;
> > +
> > + ret = i915_gem_object_set_cache_level(bo, I915_CACHE_LLC);
> > + if (ret)
> > + goto err_unref;
> > +
> > + /* PreHSW required 512K alignment, HSW requires 16M */
> > + ret = i915_gem_obj_ggtt_pin(bo, SZ_16M, 0);
> > + if (ret)
> > + goto err_unref;
> > +
> > + dev_priv->oa_pmu.oa_buffer.gtt_offset = i915_gem_obj_ggtt_offset(bo);
> > + dev_priv->oa_pmu.oa_buffer.addr = vmap_oa_buffer(bo);
>
> You can look forward to both i915_gem_object_create_internal() and
> i915_gem_object_pin_vmap()
Okey, will do, thanks.
>
> > +
> > + /* Pre-DevBDW: OABUFFER must be set with counters off,
> > + * before OASTATUS1, but after OASTATUS2 */
> > + I915_WRITE(GEN7_OASTATUS2, dev_priv->oa_pmu.oa_buffer.gtt_offset |
> > + GEN7_OASTATUS2_GGTT); /* head */
> > + I915_WRITE(GEN7_OABUFFER, dev_priv->oa_pmu.oa_buffer.gtt_offset);
> > + I915_WRITE(GEN7_OASTATUS1, dev_priv->oa_pmu.oa_buffer.gtt_offset |
> > + GEN7_OASTATUS1_OABUFFER_SIZE_16M); /* tail */
> > +
> > + DRM_DEBUG_DRIVER("OA Buffer initialized, gtt offset = 0x%x, vaddr = %p",
> > + dev_priv->oa_pmu.oa_buffer.gtt_offset,
> > + dev_priv->oa_pmu.oa_buffer.addr);
> > +
> > + return 0;
> > +
> > +err_unref:
> > + drm_gem_object_unreference_unlocked(&bo->base);
>
> But what I really what to say was:
> mutex deadlock^^^
Yikes, I've pushed an updated patch addressing this and can reply with a new patch here in a bit.
Thanks,
- Robert
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
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