[Mesa-dev] [PATCH 57/70] i965: Stage blitted buffer uploads through the common upload bo

[Daniel Vetter]

On Fri, Aug 07, 2015 at 09:14:01PM +0100, Chris Wilson wrote:
> Reuse the common upload bo for the temporary blitter storage to try and
> minimise resource usage.
> 
> Caveats: this may impose a read-read relationship on the buffer between
> the blitter and render engines, and may add stalls on old kernels.

Note that read-read has only landed in 4.2, hence we might want to hold
off on this one a bit until most distros have upgraded to this ;-)
-Daniel

> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  src/mesa/drivers/dri/i965/intel_buffer_objects.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.c b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> index 32df381..2b18e2c 100644
> --- a/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> +++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> @@ -235,17 +235,13 @@ brw_buffer_subdata(struct gl_context *ctx,
>                      (long)offset, (long)offset + size, (long)(size/1024),
>                      intel_obj->gpu_active_start,
>                      intel_obj->gpu_active_end);
> -         brw_bo *temp_bo =
> -            brw_bo_create(&brw->batch, "subdata temp", size, 64, 0);
> -
> -         brw_bo_write(temp_bo, 0, data, size, 0,
> -                      PERF_DEBUG(brw, "BufferSubData"));
> -
> +         uint32_t upload;
> +         brw_bo *temp_bo = NULL;
> +         intel_upload_data(brw, data, size, 64, &temp_bo, &upload);
>           intel_emit_linear_blit(brw,
>                                  intel_obj->buffer, offset,
> -                                temp_bo, 0,
> +                                temp_bo, upload,
>                                  size);
> -
>           brw_bo_put(temp_bo);
>           return;
>        } else {
> -- 
> 2.5.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch