On Wed, 1 Mar 2017 10:56:01 -0800
Eric Anholt <eric@xxxxxxxxxx> wrote:
> The from_cache flag was actually "the BO is invisible to userspace",
> so we can repurpose it to just zero out a cached BO and return it to
> userspace.
>
> Improves wall time for a loop of 5 glsl-algebraic-add-add-1 by
> -1.44989% +/- 0.862891% (n=28, 1 outlier removed from each that
> appeared to be other system noise)
>
> Note that there's an intel-gpu-tools test to check for the proper
> zeroing behavior here, which we continue to pass.
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/vc4/vc4_bo.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
> index 7abcd9c5dbe2..e5c7aa935b4b 100644
> --- a/drivers/gpu/drm/vc4/vc4_bo.c
> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
> @@ -211,21 +211,22 @@ struct drm_gem_object *vc4_create_object(struct drm_device *dev, size_t size)
> }
>
> struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
> - bool from_cache)
> + bool allow_unzeroed)
> {
> size_t size = roundup(unaligned_size, PAGE_SIZE);
> struct vc4_dev *vc4 = to_vc4_dev(dev);
> struct drm_gem_cma_object *cma_obj;
> + struct vc4_bo *bo;
>
> if (size == 0)
> return ERR_PTR(-EINVAL);
>
> /* First, try to get a vc4_bo from the kernel BO cache. */
> - if (from_cache) {
> - struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
> -
> - if (bo)
> - return bo;
> + bo = vc4_bo_get_from_cache(dev, size);
> + if (bo) {
> + if (!allow_unzeroed)
> + memset(bo->base.vaddr, 0, bo->base.base.size);
> + return bo;
> }
>
> cma_obj = drm_gem_cma_create(dev, size);
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