On Oct 8, 2014 11:39 AM, "Connor Abbott" <<a href="mailto:cwabbott0@gmail.com">cwabbott0@gmail.com</a>> wrote: > > On Tue, Oct 7, 2014 at 4:33 AM, Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> wrote: > > On older GENs in SIMD16 mode, we were accidentally building too much > > interference into our register classes. Since everything is divided by 2, > > the reigster allocator thinks we have 64 base registers instead of 128. > > The actual GRF mapping still needs to be doubled, but as far as the ra_set > > is concerned, we only have 64. We were accidentally adding way too much > > interference. > > Hmm, interesting. I'm not sure I quite follow the logic yet, but I > trust you that this is the right thing. Btw, just for the lols, did > you try and run shaderdb on this change? I bet we'd allocate even more > things on SIMD16 :) The SIMD16 register allocator saga continues, I > guess... Until my desktop shows up, running shader-db is never for LOLs. It takes 20 minutes per run on my poor thermally throttled ultrabook. But yes, the results would be amusing. > > > > Signed-off-by: Jason Ekstrand <<a href="mailto:jason.ekstrand@gmail.com">jason.ekstrand@gmail.com</a>> > > Cc: Connor Abbot <<a href="mailto:cwabbott0@gmail.com">cwabbott0@gmail.com</a>> > > --- > > src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp > > index fd34941..b23ddc5 100644 > > --- a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp > > +++ b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp > > @@ -179,8 +179,8 @@ brw_alloc_reg_set(struct intel_screen *screen, int reg_width) > > > > ra_reg_to_grf[reg] = j * 2; > > > > - for (int base_reg = j * 2; > > - base_reg < j * 2 + class_sizes[i]; > > + for (int base_reg = j; > > + base_reg < j + (class_sizes[i] + 1) / 2; > > base_reg++) { > > ra_add_transitive_reg_conflict(regs, base_reg, reg); > > } > > -- > > 2.1.0 > >