On Mon, 26 Nov 2012 20:02:00 +0200, Ville Syrj??l?? <ville.syrjala at linux.intel.com> wrote: > On Mon, Nov 26, 2012 at 04:28:33PM +0000, Chris Wilson wrote: > > On Mon, 26 Nov 2012 14:48:18 +0200, ville.syrjala at linux.intel.com wrote: > > > From: Ville Syrj??l?? <ville.syrjala at linux.intel.com> > > > > > > According to BSpec the ring head and tail pointers must not be > > > on the same cacheline when head > tail. The easiest way to enforce > > > this is to reduce the reported ring space. > > > > I'm going to admit blindness because I don't see that warning in the > > gen2-gen7 bspecs. Can you please give chapter and verse, and check to > > see if there is a rationale? > > It's always the last thing in the section titled 'Ring Buffer Use'. I > believe it's present in all the pre-snb internal bspecs, and it's also > in all the public docs. I can't find it in the internal snb+ bspec but > then again those don't seem to include the relevant chapter at all. Gotcha. Yes, nice catch. Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> -Chris -- Chris Wilson, Intel Open Source Technology Centre
