This reworks the implementation of brw_compile_fs() to reduce compile
time and take advantage of wider dispatch modes more aggressively than
the original logic.
The new "optimistic" PS compilation logic starts with the SIMD width
that is potentially highest performance and only compiles additional
narrower variants if that fails (typically due to spilling or hardware
restrictions), while the old "pessimistic" logic did the opposite: It
started with the narrowest SIMD width and compiled additional variants
with increasing register pressure until one of them failed to compile.
The main disadvantage of this is that selectively throwing away some
of the compiled variants based on the static analysis of their
performance behavior will no longer be possible, however this is
expected to be less useful on Xe3+ since the GRF space allocated to a
thread can be scaled up or down, which leads to less dramatic
differences in scheduling between SIMD variants.
In typical non-spilling cases where we formerly compiled SIMD16 and
SIMD32 variants of the same fragment shader, this change will halve
the number of backend compilations required to build a shader. With
multi-polygon PS dispatch enabled (which is disabled by default right
now) this has an even more dramatic effect since the number of
compiler iterations can be reduced down to a fifth in the best case
scenario.
Even though in most cases we will only attempt to return a single
binary from the pixel shader compilation, the hardware allows a pair
of PS kernels to be specified, and we'll still take advantage of this
when the multi-polygon PS kernel has the potential to have worse
performance than the single-polygon shader because only the latter
register-allocates successfully at SIMD32 -- Only in such case
(SIMD2x8 multi-polygon, SIMD32 single-polygon) we'll continue
programming both so the hardware will chose one or the other at
runtime depending on the SIMD fullness and number of polygons it can
buffer at runtime.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32664>
This avoids running the optimizer uselessly if compilation of the
current kernel failed due to some hardware (e.g. SIMD-width)
restriction. This isn't only inefficient but it can break assumptions
throughout the compiler which would lead to crashes on Xe3 when this
arises during translation from NIR.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32664>
On older hardware the "use_rep_send" compile parameter was being
implicitly used to request the compilation of the SIMD16 variant of
clear pixel shaders that require it due to hardware restrictions.
However starting on Gfx12+ this flag is never set since replicated
data clears are no longer supported, but BLORP still implicitly relies
on the SIMD16 variant being generated even though there's no way for
BLORP to explicitly request it. This doesn't cause much of a problem
right now since brw_compile_fs() typically generates a SIMD16 kernel
unless the SIMD8 kernel spills or SIMD debugging flags are enabled,
but it won't work reliably on Xe3+ since we'll start using SIMD32 more
aggressively.
In order to avoid these issues use the standard required subgroup_size
parameter from shader_info to signal that the SIMD16 variant of the
shader is needed by the caller.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32664>
No shader-db changes on any Intel platform.
fossil-db:
Meteor Lake, DG2, Tiger Lake, and Ice Lake had similar results. (Meteor Lake shown)
Totals:
Cycle count: 25096109024 -> 25096108722 (-0.00%); split: -0.00%, +0.00%
Totals from 4106 (0.51% of 797610) affected shaders:
Cycle count: 63266176 -> 63265874 (-0.00%); split: -0.01%, +0.01%
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32436>
Moving it to intel_shader_enums.h
The plan is to make it visible to OpenCL shaders.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32329>
The per-primitive have their own separate section in the FS thread
payload, and are not considered when setting the mask in
3STATE_SBE's ConstantInterpolationEnable.
This is also consistent with what is done for brw_interp_reg().
Fixes
- dEQP-VK.mesh_shader.ext.misc.clip_geom_provoking_last
- dEQP-VK.mesh_shader.ext.misc.clip_geom_and_task_shader_provoking_last
Backport-to: 24.2
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11844
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31417>
We found out that some HW changes on Xe2 make the HW avoid reading the
blend state if we're using the null_rt bit in the extended descriptor.
Since the alpha_to_coverage bit resides in the blend state, that state
is ignored and writes are going through to the depth/stencil buffers.
Disable null_rt in the color outputs if the color outputs can affect
other outputs (through alpha_to_coverage & omask).
Fixes tests in this pattern on Xe2 :
dEQP-VK.pipeline.*.multisample.alpha_to_coverage_no_color_attachment.*
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Backport-to: 24.2
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31196>
We'll want to tune this setting based on other parameters.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Backport-to: 24.2
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31196>
The long names were originally meant to map to the HW encoding but
nowadays the actual encoding values depend on gfx version, whether
instruction is 3src, etc.
Suggested by Ken.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30704>
