[Mesa-dev] [PATCH 00/16] gallium: add support for NIR as alternate IR
Rob Clark
robdclark at gmail.com
Tue Apr 5 19:57:23 UTC 2016
On Tue, Apr 5, 2016 at 3:25 PM, Marek Olšák <maraeo at gmail.com> wrote:
> Hi Rob,
>
> I have 2 questions.
>
> 1) Do you have any data about performance of shader compilation between:
>
> GLSL -> TGSI -> driver IR -> bytecode
> -and-
> GLSL -> NIR -> driver IR -> bytecode
>
I can't compare this directly, since for me it is either
glsl->tgsi->nir->driver or glsl->nir->driver.. I dropped the ir3 tgsi
f/e a while back. But from memory, NIR does have better constant
folding, for example.
There are some cases, like matrix column access, where by skipping
tgsi I should be able to do a bit better (ie. not do if/else ladder),
although I don't do this yet. (driver_location is still in units of
vec4, which is a bit of a legacy of tgsi->nir..)
I should mention, that part of my goal for this is to avoid having to
plumb half-precision support through TGSI.. and for gles apps,
half/mediump can be a big win, at least on mobile hw.
Also, not loosing the input/output/uniform names in the
glsl->nir->driver path is nice for debugging ;-)
I do need to make some more formal measurements of shader compile
time, but "seat of the pants" it feels faster.
> 2) What's the quality of the driver IR when it comes out of NIR? Is it
> optimized well?
Most of the silly/suboptimal things in resulting shader binary are ir3
issues, not NIR issues. (And I patches I pushed yesterday and today
fix the worst of those.)
I did notice the other day that NIR is missing out on some algebraic
opts in some cases, like loop unrolling that results in foo = ((bar +
1) + 1) + 1) doesn't become foo = bar + 3.. Jason did say he had some
patches for that somewhere.
BR,
-R
> Thanks,
> Marek
>
>
> On Sat, Mar 26, 2016 at 10:02 PM, Rob Clark <robdclark at gmail.com> wrote:
>> From: Rob Clark <robclark at freedesktop.org>
>>
>> Ok, hopefully (close to the) last iteration of this patchset. Quite a
>> lot of it has r-b's by now. There a few new nir bits (in particular,
>> the "lower-io-types" pass and some updates to the "lower-outputs-to-
>> temporaries" pass. Some of that will have some conflicts with stuff
>> that Jason has in-flight.. I can either rebase on top of his patchset
>> or rebase his patchset on top of mine, depending on what lands first.
>>
>> There is also a new mesa/st pass to lower builtin uniforms, to address
>> issues that I mentioned with the previous round of patches (ie. built-
>> ins getting packed differently from normal struct uniforms).
>>
>> There is also a new nir_lower_io_types pass that splits up complex
>> inputs/outputs to vec4 slots so that we can deal with galliums VBO
>> slot assignment (ie. it will already only assign VBO space to VS
>> varyings which are actually read).
>>
>> Btw, I wouldn't mind starting to push at least parts of this patchset
>> which have r-b's and don't depend on other parts that don't have r-b.
>> But I've held off for now to avoid having a bunch of nir passes that
>> aren't used upstream.
>>
>> Rob Clark (16):
>> gallium: refactor pipe_shader_state to support multiple IR's
>> gallium: add NIR as a possible IR
>> nir: add lowering pass for y-transform
>> nir: add lowering pass for glDrawPixels
>> nir: add lowering pass for glBitmap
>> nir: clamp-color-output support
>> nir: passthrough-edgeflags support
>> nir: lower-io-types pass
>> nir: move callsite of lower_outputs_to_temporaries
>> nir: rename lower_outputs_to_temporaries -> lower_io_to_temporaries
>> nir/lower-io: split out some helper fxns
>> nir/lower-io: add support for lowering inputs
>> glsl: export accessor for builtin-uniform descriptors
>> mesa/st: split the type_size calculation into it's own file
>> mesa/st: add nir pass for lowering builtin uniforms
>> mesa/st: add support for NIR as possible driver IR
>>
>> src/compiler/Makefile.sources | 8 +-
>> src/compiler/glsl/builtin_variables.cpp | 24 +-
>> src/compiler/glsl/ir.h | 3 +
>> src/compiler/nir/glsl_to_nir.cpp | 2 -
>> src/compiler/nir/nir.h | 40 +-
>> src/compiler/nir/nir_builder.h | 2 +-
>> src/compiler/nir/nir_lower_bitmap.c | 166 ++++++++
>> src/compiler/nir/nir_lower_clamp_color_outputs.c | 117 ++++++
>> src/compiler/nir/nir_lower_drawpixels.c | 252 ++++++++++++
>> src/compiler/nir/nir_lower_io_to_temporaries.c | 185 +++++++++
>> src/compiler/nir/nir_lower_io_types.c | 178 +++++++++
>> .../nir/nir_lower_outputs_to_temporaries.c | 133 -------
>> src/compiler/nir/nir_lower_passthrough_edgeflags.c | 82 ++++
>> src/compiler/nir/nir_lower_wpos_ytransform.c | 310 +++++++++++++++
>> src/gallium/auxiliary/hud/hud_context.c | 9 +-
>> src/gallium/auxiliary/postprocess/pp_run.c | 3 +-
>> src/gallium/auxiliary/tgsi/tgsi_ureg.c | 4 +-
>> src/gallium/auxiliary/util/u_simple_shaders.c | 18 +-
>> src/gallium/auxiliary/util/u_tests.c | 3 +-
>> .../drivers/freedreno/ir3/ir3_compiler_nir.c | 8 +
>> src/gallium/include/pipe/p_defines.h | 13 +-
>> src/gallium/include/pipe/p_screen.h | 9 +
>> src/gallium/include/pipe/p_state.h | 32 +-
>> src/mesa/Makefile.sources | 5 +
>> src/mesa/drivers/dri/i965/brw_nir.c | 1 +
>> src/mesa/state_tracker/st_glsl_to_nir.cpp | 425 +++++++++++++++++++++
>> src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 104 ++---
>> src/mesa/state_tracker/st_glsl_to_tgsi.h | 5 +
>> src/mesa/state_tracker/st_glsl_types.cpp | 98 +++++
>> src/mesa/state_tracker/st_glsl_types.h | 44 +++
>> src/mesa/state_tracker/st_nir.h | 60 +++
>> src/mesa/state_tracker/st_nir_lower_builtin.c | 242 ++++++++++++
>> src/mesa/state_tracker/st_program.c | 148 ++++++-
>> src/mesa/state_tracker/st_program.h | 6 +
>> 34 files changed, 2487 insertions(+), 252 deletions(-)
>> create mode 100644 src/compiler/nir/nir_lower_bitmap.c
>> create mode 100644 src/compiler/nir/nir_lower_clamp_color_outputs.c
>> create mode 100644 src/compiler/nir/nir_lower_drawpixels.c
>> create mode 100644 src/compiler/nir/nir_lower_io_to_temporaries.c
>> create mode 100644 src/compiler/nir/nir_lower_io_types.c
>> delete mode 100644 src/compiler/nir/nir_lower_outputs_to_temporaries.c
>> create mode 100644 src/compiler/nir/nir_lower_passthrough_edgeflags.c
>> create mode 100644 src/compiler/nir/nir_lower_wpos_ytransform.c
>> create mode 100644 src/mesa/state_tracker/st_glsl_to_nir.cpp
>> create mode 100644 src/mesa/state_tracker/st_glsl_types.cpp
>> create mode 100644 src/mesa/state_tracker/st_glsl_types.h
>> create mode 100644 src/mesa/state_tracker/st_nir.h
>> create mode 100644 src/mesa/state_tracker/st_nir_lower_builtin.c
>>
>> --
>> 2.5.5
>>
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