<div class="gmail_quote">On 19 September 2012 13:27, Kenneth Graunke <<a href="mailto:kenneth@whitecape.org" target="_blank">kenneth@whitecape.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Data port reads are absurdly slow on Ivybridge due to cache issues. The LD message ignores the sampler unit index and SAMPLER_STATE pointer, instead relying on hard-wired default state. Thus, there's no need to worry about running out of sampler units or providing SAMPLER_STATE; this small patch should be all that's required. NOTE: This is a candidate for all release branches. </blockquote><div> </div><div>Given that this affects only performance and not correctness, I'm having trouble convincing myself that this patch should be a candidate for release branches. Don't we usually try to restrict release cherry-picks to things like rendering issues and avoiding GPU hangs?</div> <div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Signed-off-by: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> --- src/mesa/drivers/dri/i965/brw_fs.h | 3 +++ src/mesa/drivers/dri/i965/brw_fs_emit.cpp | 36 ++++++++++++++++++++++++++++++- 2 files changed, 38 insertions(+), 1 deletion(-) I did this a long time ago for VS pull constant loading, which resulted in a 2-5x speedup for certain benchmarks. Apparently at the time I never got FS pull constant loading working, and didn't have a benchmark that needed it, so I never finished and pushed it. Now I have a game that needs it. No concrete data as I haven't figured out how to get consistent FPS numbers out of it. diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h index e69de31..b5f2152 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.h +++ b/src/mesa/drivers/dri/i965/brw_fs.h @@ -295,6 +295,9 @@ public: void generate_pull_constant_load(fs_inst *inst, struct brw_reg dst, struct brw_reg index, struct brw_reg offset); + void gen7_generate_pull_constant_load(fs_inst *inst, struct brw_reg dst, + struct brw_reg index, + struct brw_reg offset); void generate_mov_dispatch_to_flags(); void emit_dummy_fs(); diff --git a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp index 5900c0e..4059660 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp @@ -585,6 +585,37 @@ fs_visitor::generate_unspill(fs_inst *inst, struct brw_reg dst) } void +fs_visitor::gen7_generate_pull_constant_load(fs_inst *inst, struct brw_reg dst, + struct brw_reg index, + struct brw_reg offset) +{ + assert(intel->gen == 7); + assert(index.file == BRW_IMMEDIATE_VALUE && + index.type == BRW_REGISTER_TYPE_UD); + assert(offset.file == BRW_IMMEDIATE_VALUE && + offset.type == BRW_REGISTER_TYPE_UD); + uint32_t surf_index = index.dw1.ud; + uint32_t read_offset = offset.dw1.ud; + + /* offset is an IMM; SEND needs to be from a GRF. */ + offset = retype(brw_vec8_grf(127, 0), BRW_REGISTER_TYPE_UD); + brw_MOV(p, offset, brw_imm_ud(read_offset / 16)); + + brw_instruction *insn = brw_next_insn(p, BRW_OPCODE_SEND); + brw_set_dest(p, insn, dst); + brw_set_src0(p, insn, offset); + brw_set_sampler_message(p, insn, + surf_index, + 0, /* LD message ignores sampler unit */ + GEN5_SAMPLER_MESSAGE_SAMPLE_LD, + 1, /* rlen */ + 1, /* mlen */ + false, /* no header */ + BRW_SAMPLER_SIMD_MODE_SIMD4X2, + 0); +} + +void fs_visitor::generate_pull_constant_load(fs_inst *inst, struct brw_reg dst, struct brw_reg index, struct brw_reg offset) @@ -980,7 +1011,10 @@ fs_visitor::generate_code() break; case FS_OPCODE_PULL_CONSTANT_LOAD: - generate_pull_constant_load(inst, dst, src[0], src[1]); + if (intel->gen == 7) + gen7_generate_pull_constant_load(inst, dst, src[0], src[1]); + else + generate_pull_constant_load(inst, dst, src[0], src[1]); break; case FS_OPCODE_FB_WRITE: -- 1.7.11.4 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" target="_blank">http://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div>