[Mesa-dev] [PATCH 1/5] i965: Split shader_time entries into separate cachelines.

[Eric Anholt]

This avoids some snooping overhead between EUs processing separate shaders
(so VS versus FS).

Improves performance of a minecraft trace with shader_time by 28.9% +/-
18.3% (n=7), and performance of my old GLSL demo by 93.7% +/- 0.8% (n=4).
---
 src/mesa/drivers/dri/i965/brw_fs.cpp    |    2 +-
 src/mesa/drivers/dri/i965/brw_program.c |    2 +-
 src/mesa/drivers/dri/i965/brw_vec4.cpp  |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 8ce3954..dd3baa9 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -621,7 +621,7 @@ fs_visitor::emit_shader_time_write(enum shader_time_shader_type type,
 
    fs_reg offset_mrf = fs_reg(MRF, base_mrf);
    offset_mrf.type = BRW_REGISTER_TYPE_UD;
-   emit(MOV(offset_mrf, fs_reg(shader_time_index * 4)));
+   emit(MOV(offset_mrf, fs_reg(shader_time_index * 64)));
 
    fs_reg time_mrf = fs_reg(MRF, base_mrf + 1);
    time_mrf.type = BRW_REGISTER_TYPE_UD;
diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
index 75eb6bc..c1aeefc 100644
--- a/src/mesa/drivers/dri/i965/brw_program.c
+++ b/src/mesa/drivers/dri/i965/brw_program.c
@@ -409,7 +409,7 @@ brw_collect_shader_time(struct brw_context *brw)
    uint32_t *times = brw->shader_time.bo->virtual;
 
    for (int i = 0; i < brw->shader_time.num_entries; i++) {
-      brw->shader_time.cumulative[i] += times[i];
+      brw->shader_time.cumulative[i] += times[i * 16];
    }
 
    /* Zero the BO out to clear it out for our next collection.
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index f319f32..b87d62b 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -1225,7 +1225,7 @@ vec4_visitor::emit_shader_time_write(enum shader_time_shader_type type,
 
    dst_reg offset_mrf = dst_reg(MRF, base_mrf);
    offset_mrf.type = BRW_REGISTER_TYPE_UD;
-   emit(MOV(offset_mrf, src_reg(shader_time_index * 4)));
+   emit(MOV(offset_mrf, src_reg(shader_time_index * 64)));
 
    dst_reg time_mrf = dst_reg(MRF, base_mrf + 1);
    time_mrf.type = BRW_REGISTER_TYPE_UD;
-- 
1.7.10.4