On 2018-03-26 08:23:13, Juan A. Suarez Romero wrote:
> On Wed, 2018-03-07 at 00:16 -0800, Jordan Justen wrote:
> > Ken suggested that we might be underallocating scratch space on HD
> > 400. Allocating scratch space as though there was actually 8 EUs
> > seems to help with a GPU hang seen on synmark CSDof.
> >
>
> FYI, in order to pick this commit for next 17.3 stable release, I need to pick
> also:
>
> commit f9d5a7add42af5a2e4410526d1480a08f41317ae
> Author: Jordan Justen <jordan.l.jus...@intel.com>
> Date: Tue Oct 31 00:34:32 2017 -0700
>
> i965: Calculate thread_count in brw_alloc_stage_scratch
I believe that this commit lead to a regression with compute shaders,
which was fixed by:
commit a16dc04ad51c32e5c7d136e4dd6273d983385d3f
Author: Kenneth Graunke <kenn...@whitecape.org>
Date: Tue Oct 31 00:56:24 2017 -0700
i965: properly initialize brw->cs.base.stage to MESA_SHADER_COMPUTE
You should probably add Ken's a16dc04ad51c before f9d5a7add42a.
-Jordan
>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104636
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105290
> > Cc: Kenneth Graunke <kenn...@whitecape.org>
> > Cc: Eero Tamminen <eero.t.tammi...@intel.com>
> > Cc: <mesa-sta...@lists.freedesktop.org>
> > Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
> > ---
> > src/mesa/drivers/dri/i965/brw_program.c | 44
> > ++++++++++++++++++++-------------
> > 1 file changed, 27 insertions(+), 17 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_program.c
> > b/src/mesa/drivers/dri/i965/brw_program.c
> > index 527f003977b..c121136c439 100644
> > --- a/src/mesa/drivers/dri/i965/brw_program.c
> > +++ b/src/mesa/drivers/dri/i965/brw_program.c
> > @@ -402,23 +402,33 @@ brw_alloc_stage_scratch(struct brw_context *brw,
> > if (devinfo->gen >= 9)
> > subslices = 4 * brw->screen->devinfo.num_slices;
> >
> > - /* WaCSScratchSize:hsw
> > - *
> > - * Haswell's scratch space address calculation appears to be sparse
> > - * rather than tightly packed. The Thread ID has bits indicating
> > - * which subslice, EU within a subslice, and thread within an EU
> > - * it is. There's a maximum of two slices and two subslices, so
> > these
> > - * can be stored with a single bit. Even though there are only 10
> > EUs
> > - * per subslice, this is stored in 4 bits, so there's an effective
> > - * maximum value of 16 EUs. Similarly, although there are only 7
> > - * threads per EU, this is stored in a 3 bit number, giving an
> > effective
> > - * maximum value of 8 threads per EU.
> > - *
> > - * This means that we need to use 16 * 8 instead of 10 * 7 for the
> > - * number of threads per subslice.
> > - */
> > - const unsigned scratch_ids_per_subslice =
> > - devinfo->is_haswell ? 16 * 8 : devinfo->max_cs_threads;
> > + unsigned scratch_ids_per_subslice;
> > + if (devinfo->is_haswell) {
> > + /* WaCSScratchSize:hsw
> > + *
> > + * Haswell's scratch space address calculation appears to be
> > sparse
> > + * rather than tightly packed. The Thread ID has bits indicating
> > + * which subslice, EU within a subslice, and thread within an EU
> > it
> > + * is. There's a maximum of two slices and two subslices, so these
> > + * can be stored with a single bit. Even though there are only 10
> > EUs
> > + * per subslice, this is stored in 4 bits, so there's an effective
> > + * maximum value of 16 EUs. Similarly, although there are only 7
> > + * threads per EU, this is stored in a 3 bit number, giving an
> > + * effective maximum value of 8 threads per EU.
> > + *
> > + * This means that we need to use 16 * 8 instead of 10 * 7 for the
> > + * number of threads per subslice.
> > + */
> > + scratch_ids_per_subslice = 16 * 8;
> > + } else if (devinfo->is_cherryview) {
> > + /* For Cherryview, it appears that the scratch addresses for the
> > 6 EU
> > + * devices may still generate compute scratch addresses covering
> > the
> > + * same range as 8 EU.
> > + */
> > + scratch_ids_per_subslice = 8 * 7;
> > + } else {
> > + scratch_ids_per_subslice = devinfo->max_cs_threads;
> > + }
> >
> > thread_count = scratch_ids_per_subslice * subslices;
> > break;
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