On Tue, Sep 15, 2015 at 11:37:22AM -0700, Kristian Høgsberg wrote: > On Thu, Sep 10, 2015 at 03:35:18PM +0200, Iago Toral Quiroga wrote: > > This is the same we do for other things like uniforms because it ensures > > optimal performance. > > > > Reviewed-by: Jordan Justen <jordan.l.jus...@intel.com> > > --- > > src/mesa/drivers/dri/i965/brw_context.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/src/mesa/drivers/dri/i965/brw_context.c > > b/src/mesa/drivers/dri/i965/brw_context.c > > index 907b2a0..c8e8a68 100644 > > --- a/src/mesa/drivers/dri/i965/brw_context.c > > +++ b/src/mesa/drivers/dri/i965/brw_context.c > > @@ -558,6 +558,7 @@ brw_initialize_context_constants(struct brw_context > > *brw) > > * However, unaligned accesses are slower, so enforce buffer alignment. > > */ > > ctx->Const.UniformBufferOffsetAlignment = 16; > > + ctx->Const.ShaderStorageBufferOffsetAlignment = 16; > > This should be a cacheline (64 bytes) so that we can safely have the > CPU and GPU writing the same SSBO on non-cachecoherent systems (our > Atom CPUs). With UBOs, the GPU never writes, so there's no > problem. For an SSBO, the GPU and the CPU can be updating disjoint > regions of the buffer simultaneously and that will break if the > regions overlap the same cacheline. > > With that change, > > Reviewed-by: Kristian Høgsberg <k...@bitplanet.net> >
I know nothing about SSBOs... I agree with Kristian assuming something in the API disallows simultaneous access to the same region from CPU and GPU - in which case, cacheline alignment doesn't buy anything. Also, when you make the change, please add a comment about why its 64. > > ctx->Const.TextureBufferOffsetAlignment = 16; > > ctx->Const.MaxTextureBufferSize = 128 * 1024 * 1024; > > > > -- > > 1.9.1 > > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
