Re: [PATCH 1/7] drm/i915: Mark context switch likely

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 05 Apr 2013, Ben Widawsky <ben@bwidawsk.net> wrote:
> Only the very first switch doesn't take the path.
>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_gem_context.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 94d873a..aa080ea 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -390,7 +390,7 @@ static int do_switch(struct i915_hw_context *to)
>  	 * is a bit suboptimal because the retiring can occur simply after the
>  	 * MI_SET_CONTEXT instead of when the next seqno has completed.
>  	 */
> -	if (from_obj != NULL) {
> +	if (likely(from_obj)) {

Looking at the function, is this, uh, likely to make a difference?

Same goes for the unlikely in patches 4/7. (Yes, patch_es_ 4/7 - there's
*two* patches 4/7 in the series! :o)

I'm just generally wary of adding (un)likely annotations. I don't think
it matters that the annotation itself is obviously correct; IMHO the
performance impact should matter.

</bikeshed>

BR,
Jani.


>  		from_obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;
>  		i915_gem_object_move_to_active(from_obj, ring);
>  		/* As long as MI_SET_CONTEXT is serializing, ie. it flushes the
> -- 
> 1.8.2
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx