[Mesa-dev] [PATCH 0/6] An attempt to speed up register set creation

Jason Ekstrand jason at jlekstrand.net
Sat Aug 15 11:31:21 PDT 2015

This series was inspired by a patch from Chris Willson entitled
"util/register_allocate: Compute transitive conflicts using 2-passes"

The basic idea is the same: Instead of marking transitive conflicts as you
go, just mark conflicts with the base register up-front and apply
transitivity later.  One nice result of this is that with this and
pre-calculated q-values, we can get rid of the expensive conflict lists
that we build inside the allocator.  This takes a full piglit run on 32-bit
baytrail from about 28 minutes to 22 due to the reduction in screen
creation time.

The last patch makes BITSET_WORD a 64-bit value on 64-bit systems.  I don't
actually have perf numbers for that, but it should help ra setup as well as
liveness analysis and a whole host of other compiler tasks.

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Eric Anholt <eric at anholt.net>

Jason Ekstrand (6):
  util/bitset: Add a BITSET_FOREACH_SET macro
  util/ra: Add a function for making all conflicts on a register
  i965/reg_allocate: Use make_reg_conflicts_transitive
  util/ra: Make allocating conflict lists optional
  gallium/util: Add an implementation of ffsl
  util/bitset: Use a long for bitset words

 src/gallium/auxiliary/util/u_math.h                | 12 ++++++
 src/gallium/drivers/freedreno/ir3/ir3_ra.c         |  2 +-
 .../drivers/r300/compiler/radeon_pair_regalloc.c   |  3 +-
 src/gallium/drivers/vc4/vc4_register_allocate.c    |  2 +-
 src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp  | 12 ++++--
 .../drivers/dri/i965/brw_vec4_reg_allocate.cpp     |  7 +++-
 src/util/bitset.h                                  | 37 +++++++++++++++-
 src/util/register_allocate.c                       | 49 ++++++++++++++++++----
 src/util/register_allocate.h                       |  4 +-
 9 files changed, 109 insertions(+), 19 deletions(-)


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