On 28/10/18 12:18 pm, Jason Ekstrand wrote:
On Sat, Oct 27, 2018 at 8:03 PM Timothy Arceri <[email protected]
<mailto:[email protected]>> wrote:
From: Timothy Arceri <[email protected]>
Commit 8d8222461f9d7f49 caused substantially more URB messages in
geometry and tessellation shaders (due to enabling
nir_lower_io_to_scalar_early). This combines io again to avoid
this regression while still allowing link time optimisation of
components.
Shader-db results (SKL):
total instructions in shared programs: 13107449 -> 13104666 (-0.02%)
instructions in affected programs: 304803 -> 302020 (-0.91%)
helped: 1136
HURT: 409
total cycles in shared programs: 332066434 -> 332125306 (0.02%)
cycles in affected programs: 70735188 -> 70794060 (0.08%)
helped: 11797
HURT: 13257
LOST: 2
GAINED: 1
Most of the cycle/instruction changes is with fragment shaders.
Why are we running it on fragment shaders?
The pass was originally written for radv/radeonsi and as far as I can
tell this is what LLVM does for those drivers.
They don't benefit at all
from vector I/O. For that matter, why does it affect them at all?
Just a guess from what I have seen in radv but it's probably a scheduler
thing. e.g We do the (vec4) load at the start of the shader in some
cases one of the components might not be used until much later. In RADV
this was adding to VGPR register pressure.
--Jason
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107510
---
src/intel/vulkan/anv_pipeline.c | 6 ++++++
src/mesa/drivers/dri/i965/brw_link.cpp | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/src/intel/vulkan/anv_pipeline.c
b/src/intel/vulkan/anv_pipeline.c
index 7c9b1230115..63acb3cc25e 100644
--- a/src/intel/vulkan/anv_pipeline.c
+++ b/src/intel/vulkan/anv_pipeline.c
@@ -1016,6 +1016,12 @@ anv_pipeline_compile_graphics(struct
anv_pipeline *pipeline,
void *stage_ctx = ralloc_context(NULL);
+ if (nir_opt_vectorize_io(stages[s].nir)) {
+ brw_nir_optimize(stages[s].nir, compiler,
+
compiler->scalar_stage[stages[s].nir->info.stage],
+ false);
+ }
+
anv_pipeline_lower_nir(pipeline, stage_ctx, &stages[s], layout);
const unsigned *code;
diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp
b/src/mesa/drivers/dri/i965/brw_link.cpp
index 2cbb1e0b879..0bcd73af04c 100644
--- a/src/mesa/drivers/dri/i965/brw_link.cpp
+++ b/src/mesa/drivers/dri/i965/brw_link.cpp
@@ -319,6 +319,12 @@ brw_link_shader(struct gl_context *ctx, struct
gl_shader_program *shProg)
struct gl_program *prog = shader->Program;
+ if (nir_opt_vectorize_io(prog->nir)) {
+ brw_nir_optimize(prog->nir, compiler,
+ compiler->scalar_stage[prog->info.stage],
+ false);
+ }
+
_mesa_update_shader_textures_used(shProg, prog);
brw_shader_gather_info(prog->nir, prog);
--
2.17.2
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