[Mesa-dev] [PATCH 1/2] mesa: Add a streaming load memcpy implementation.

[Steven Newbury]

On Wed, 2013-11-06 at 17:06 -0800, Chad Versace wrote:
> On 11/06/2013 02:44 PM, Eric Anholt wrote:
> > Matt Turner <mattst88 at gmail.com> writes:
> >
> >> Uses SSE 4.1's MOVNTDQA instruction (streaming load) to read from
> >> uncached memory without polluting the cache.
> >> ---
> >> We should add runtime detection support later.
> >
> > I'd really like to see runtime detection with this.  Effectively not
> > supporting this on 32-bit sucks, and doing it this way will encourage
> > people to use compiler flags to get this path, even when those compiler
> > flags hurt performance in general (in my testing, at least).
> 
> This patch, as-is without runtime detection, benefits platform-specific
> Linux builds such as ChromiumOS. Seeing that the patch benefits
> immediately for some distros, I see no reason to block the patch for lack
> of runtime detection.
> 
> I would also like to see runtime detection as a follow-up.
> 
> Patch 1 is
> Reviewed-by: Chad Versace <chad.versace at linux.intel.com>
> 
> By the way, I tested this series by playing around on ChromiumOS,
> but I don't believe that warrants a Tested-by.
> 
Building with --disable-asm results in:
dlopen /usr/lib64/dri/i965_dri.so failed (/usr/lib64/dri/i965_dri.so:
undefined symbol: _mesa_streaming_load_memcpy

The i965 driver either needs to only use _mesa_streaming_load_memcpy()
when asm is enabled, or there needs to be a non-asm implementation in
streaming_load_memcpy.c.