On Fri, Sep 11, 2015 at 12:12:15PM -0700, Jordan Justen wrote:
> On 2015-09-10 16:59:12, Ben Widawsky wrote:
> > All SKL SKUs except the lowest one which has half the L3 size actually have
> > 384K
>
> These commit message lines seem to wrap a bit long. This first line is
> 80 characters.
>
> > of URB per slice.
> >
> > For once, I can explain how this mistake was made and how it was missed in
> > review... Historically when we enable a platform and put the production
> > sizes,
> > you can simply look at the "smallest" SKU and see what its URB size is (and
> > we
> > assumed it was the 1 slice variant). Since on newer platforms the URB sizes
> > are
> > scaled automatically by HW, this was sufficient. On SKL, this is a bit
> > different
> > as the lowest SKU actually has half of the L3 fused off. GT2 is the 1 slice
> > (not
> > GT1) variant and it has 384K.
> >
> > There are no Jenkins tests fixed (or regressions) and we don't expect any
> > fixes
> > here because you can always run with less URB size - this potentially
> > improves
> > performance.
>
> It would be nice if we were able to find a benchmark that improves
> from this change. If we can't then maybe we should just remove this
> paragraph. It seems like the right change regardless.
>
> Reviewed-by: Jordan Justen <jordan.l.jus...@intel.com>
I think what I'd like to do is run the perf data to make sure there are at least
no regressions since I am proposing it for stable... Maybe if I don't get around
to that before the next stable release, we'll bail on it for 10.6
>
> > Thanks to Sarah for bringing this to my attention.
>
> Reported-by?
>
> > Cc: "10.6 11.0" <mesa-sta...@lists.freedesktop.org>
> > Cc: Neil Roberts <n...@linux.intel.com>
> > Cc: Sarah Sharp <sarah.a.sh...@intel.com>
> > Cc: Jordan Justen <jordan.l.jus...@intel.com>
> > Signed-off-by: Ben Widawsky <b...@bwidawsk.net>
> > ---
> > src/mesa/drivers/dri/i965/brw_device_info.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_device_info.c
> > b/src/mesa/drivers/dri/i965/brw_device_info.c
> > index 7ad3a2f..a6a3bb6 100644
> > --- a/src/mesa/drivers/dri/i965/brw_device_info.c
> > +++ b/src/mesa/drivers/dri/i965/brw_device_info.c
> > @@ -314,7 +314,7 @@ static const struct brw_device_info brw_device_info_chv
> > = {
> > .max_wm_threads = 64 * 6, \
> > .max_cs_threads = 56, \
> > .urb = { \
> > - .size = 192, \
> > + .size = 384, \
> > .min_vs_entries = 64, \
> > .max_vs_entries = 1856, \
> > .max_hs_entries = 672, \
> > @@ -324,6 +324,7 @@ static const struct brw_device_info brw_device_info_chv
> > = {
> >
> > static const struct brw_device_info brw_device_info_skl_gt1 = {
> > GEN9_FEATURES, .gt = 1,
> > + .urb.size = 192,
> > };
> >
> > static const struct brw_device_info brw_device_info_skl_gt2 = {
> > --
> > 2.5.1
> >
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