In SIMD16 and SIMD32, storing convergent values in full 16- or
32-channel registers is wasteful. It wastes register space, and in most
cases on SIMD32, it wastes instructions. Our register allocator is not
clever enough to handle scalar allocations. It's fundamental unit of
allocation is SIMD8. Start treating convergent values as SIMD8.
Add a tracking bit in brw_reg to specify that a register represents a
convergent, scalar value. This has two implications:
1. All channels of the SIMD8 register must contain the same value. In
general, this means that writes to the register must be
force_writemask_all and exec_size = 8;
2. Reads of this register can (and should) use <0,1,0> stride. SIMD8
instructions that have restrictions on source stride can us <8,8,1>.
Values that are vectors (e.g., results of load_uniform or texture
operations) will be stored as multiple SIMD8 hardware registers.
v2: brw_fs_opt_copy_propagation_defs fix from Ken. Fix for Xe2.
v3: Eliminte offset_to_scalar(). Remove mention of vec4 backend in
brw_reg.h. Both suggested by Caio. The offset_to_scalar() change
necessitates some trickery in the fs_builder offset() function, but I
think this is an improvement overall. There is also some rework in
find_value_for_offset to account for the possibility that is_scalar
sources in LOAD_PAYLOAD might be <8;8,1> or <0;1,0>.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29884>
Some uses of the old pattern still exist. The use in brw_fs_nir.cpp is
deleted by commits !29884. The use in brw_lower_logical_sends.cpp seems
different, so I decided to keep it.
The next commit wants to use this.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32041>
If we have a non-register-aligned source, MOV it to a new register
so that the invariant expected when generating SHADER_OPCODE_BROADCAST
is respected.
Added to ensure a later patch won't hit the `src.subnr == 0` assertion
in brw_broadcast() generation code.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31029>
Include in the helper which already take care of using exec_all() and
taking the first component of the result. Both are expected by
SHADER_OPCODE_BROADCAST.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31029>
When INTEL_DEBUG=ann is also set, the disassembler would annotate the
output with either a string or the string verison of a NIR instruction.
This was done by keeping two pointers (but only using one at a time).
Change the code to print the instruction into a string instead of
keeping it pointer around (peg the string to the shader). That way,
only one pointer is needed for annotations. Because that serialization
is not free, only do that when the environment variable is set.
Since we are here, move the annotation string field to the end, moving
it to the least commonly used cacheline. Further packing might allow
the entire fs_inst to fit in two cachelines.
For release builds, don't even add the debug annotation to the struct.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30822>
Instead of emitting a single one at the top, and making reference to it,
emit the virtual instruction as needed and let CSE do its job.
Since load_subgroup_invocation now can appear not at the start of the
shader, use UNDEF in all cases to ensure that the liveness of the
destination doesn't extend to the first partial write done here (it was
being used only for SIMD > 8 before).
Note this option was considered in the past
6132992cdb but at the time dismissed. The
difference now is that the lowering of the virtual instruction happens
earlier than the scheduling.
The motivation for this change is to allow passes other than the NIR
conversion to use this value. The alternative of storing a `brw_reg` in
the shader (instead of NIR state) gets complicated by passes like
compact_vgrfs, that move VGRFs around (and update the instructions).
This and maybe other passes would have to care about the brw_reg.
Fossil-db numbers, TGL
```
*** Shaders only in 'after' results are ignored:
steam-native/shadow_of_the_tomb_raider/c683ea5067ee157d/fs.32/0, steam-native/shadow_of_the_tomb_raider/f4df450c3cef40b4/fs.32/0, steam-native/shadow_of_the_tomb_raider/94b708fb8e3d9597/fs.32/0, steam-native/shadow_of_the_tomb_raider/19d44c328edabd30/fs.32/0, steam-native/shadow_of_the_tomb_raider/8a7dcbd5a74a19bf/fs.32/0, and 366 more
from 4 apps: steam-dxvk/alan_wake, steam-dxvk/batman_arkham_city_goty, steam-dxvk/batman_arkham_origins, steam-native/shadow_of_the_tomb_raider
*** Shaders only in 'before' results are ignored:
steam-dxvk/octopath_traveler/aaa3d10acb726906/fs.32/0, steam-dxvk/batman_arkham_origins/e6872ae23569c35f/fs.32/0, steam-dxvk/octopath_traveler/fd33a99fa5c271a8/fs.32/0, steam-dxvk/octopath_traveler/9a077cdc16f24520/fs.32/0, steam-dxvk/batman_arkham_city_goty/fac7b438ad52f622/fs.32/0, and 12 more
from 4 apps: steam-dxvk/batman_arkham_city_goty, steam-dxvk/batman_arkham_origins, steam-dxvk/octopath_traveler, steam-native/shadow_of_the_tomb_raider
Totals:
Instrs: 149752381 -> 149751337 (-0.00%); split: -0.00%, +0.00%
Cycle count: 11553609349 -> 11549970294 (-0.03%); split: -0.06%, +0.03%
Spill count: 42763 -> 42764 (+0.00%); split: -0.01%, +0.01%
Fill count: 75650 -> 75651 (+0.00%); split: -0.00%, +0.01%
Max live registers: 31725096 -> 31671792 (-0.17%)
Max dispatch width: 5546008 -> 5551672 (+0.10%); split: +0.11%, -0.00%
Totals from 52574 (8.34% of 630441) affected shaders:
Instrs: 9535159 -> 9534115 (-0.01%); split: -0.03%, +0.02%
Cycle count: 1006627109 -> 1002988054 (-0.36%); split: -0.65%, +0.29%
Spill count: 11588 -> 11589 (+0.01%); split: -0.03%, +0.03%
Fill count: 21057 -> 21058 (+0.00%); split: -0.01%, +0.02%
Max live registers: 1992493 -> 1939189 (-2.68%)
Max dispatch width: 559696 -> 565360 (+1.01%); split: +1.06%, -0.05%
```
and DG2
```
*** Shaders only in 'after' results are ignored:
steam-native/shadow_of_the_tomb_raider/1f95a9d3db21df85/fs.32/0, steam-native/shadow_of_the_tomb_raider/56b87c4a46613a2a/fs.32/0, steam-native/shadow_of_the_tomb_raider/a74b4137f85dbbd3/fs.32/0, steam-native/shadow_of_the_tomb_raider/e07e38d3f48e8402/fs.32/0, steam-native/shadow_of_the_tomb_raider/206336789c48996c/fs.32/0, and 268 more
from 4 apps: steam-dxvk/alan_wake, steam-dxvk/batman_arkham_city_goty, steam-dxvk/batman_arkham_origins, steam-native/shadow_of_the_tomb_raider
*** Shaders only in 'before' results are ignored:
steam-native/shadow_of_the_tomb_raider/0420d7c3a2ea99ec/fs.32/0, steam-native/shadow_of_the_tomb_raider/2ff39f8bf7d24abb/fs.32/0, steam-native/shadow_of_the_tomb_raider/92d7be2824bd9659/fs.32/0, steam-native/shadow_of_the_tomb_raider/f09ca6d2ecf18015/fs.32/0, steam-native/shadow_of_the_tomb_raider/490f8ffd59e52949/fs.32/0, and 205 more
from 3 apps: steam-dxvk/batman_arkham_city_goty, steam-dxvk/batman_arkham_origins, steam-native/shadow_of_the_tomb_raider
Totals:
Instrs: 151597619 -> 151599914 (+0.00%); split: -0.00%, +0.00%
Subgroup size: 7699776 -> 7699784 (+0.00%)
Cycle count: 12738501989 -> 12739841170 (+0.01%); split: -0.01%, +0.02%
Spill count: 61283 -> 61274 (-0.01%)
Fill count: 119886 -> 119849 (-0.03%)
Max live registers: 31810432 -> 31758920 (-0.16%)
Max dispatch width: 5540128 -> 5541136 (+0.02%); split: +0.08%, -0.06%
Totals from 49286 (7.81% of 631231) affected shaders:
Instrs: 8607753 -> 8610048 (+0.03%); split: -0.01%, +0.04%
Subgroup size: 857752 -> 857760 (+0.00%)
Cycle count: 305939495 -> 307278676 (+0.44%); split: -0.28%, +0.72%
Spill count: 6339 -> 6330 (-0.14%)
Fill count: 12571 -> 12534 (-0.29%)
Max live registers: 1788346 -> 1736834 (-2.88%)
Max dispatch width: 510920 -> 511928 (+0.20%); split: +0.85%, -0.66%
```
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30489>
We can do CSEL on F, HF, *W, and *D on Gfx11+. Gfx9 can only do F.
We can lower unsupported types to CMP+CSEL, allowing us to use CSEL
in the IR and not worry about the limitations.
Rework: (Sagar)
- Update validation pass for CSEL
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29316>
There are a lot of places where we add 0 to an offset. Avoiding
generating this can save us algebraic + copy_propagation later.
Cuts compile time in Borderlands 3 by -0.590631% +/- 0.170108% (n=25).
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29849>
Instead of replicating the whole thing in macros, just make an alu2()
function and use that in the wrappers. It ought to get inlined anyway.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29849>
This gathers a number of sources into a contiguous vector register,
typically using LOAD_PAYLOAD. However, it uses MOV for a single source.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28666>
These were removed with Icelake. While they technically still exist on
Skylake, which this compiler supports, we have never used these opcodes
in the 14 years we could have done so. So just scrap them.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29665>
For CMP/CMPN, use src0 type if destination is null otherwise get the
src0 type register with destination register size.
This fixes dEQP-VK.glsl.builtin_var.frontfacing.* tests cases on Xe2+.
Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28679>
This gathers a number of sources into a contiguous vector register.
Eventually, the plan is that it will use a MOV for a single source,
or LOAD_PAYLOAD for multiple sources. For now, it emits a series of
MOVs to allow us to rewrite a bunch of existing code to use the new
helper, then change them all over at once later.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28971>
With the previous commit, we now have new builder helpers that will
allocate a temporary destination for us. So we can eliminate a lot
of the temporary naming and declarations, and build up expressions.
In a number of cases here, the code was confusingly mixing D-type
addresses with UD-immediates, or expecting a UD destination. But the
underlying values should always be positive anyway. To accomodate the
type inference restriction that the base types much match, we switch
these over to be purely UD calculations. It's cleaner to do so anyway.
Compared to the old code, this may in some cases allocate additional
temporary registers for subexpressions.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28957>
In many cases, we calculate an expression by generating a series of
instructions. We'd either overwrite the same register repeatedly,
or call vgrf(BRW_TYPE_X) repeatedly to allocate temporaries for each
intermediate step. In many cases, we overwrote the same register simply
because allocating and naming temporaries for each step was annoying.
This commit adds new builder helpers that will allocate a temporary
destination for you, using simple type interference: unary operations
use the source type, and binary operations require a matching base type
and return the largest of the two types.
The helpers return the destination register, allowing us to write in an
expression-tree style, chaining together builder operations to produce
whole values. Sort of like nir_builder. We still optionally will write
out the fs_inst pointer in case the caller wants to do things like set
predicates or saturation.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28957>
Both of these helpers do the same thing. We now have brw_type_size_bits
and brw_type_size_bytes and can use whichever makes sense in that place.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28847>
Outside SIMD1 instructions, a destination stride of zero doesn't make
any sense. When such strides exist, they would be fixed by the FS
generator. Currently the only place that intentionally generates such a
stride is setup_barrier_message_payload_gfx125, and this commit changes
that.
The existence of a zero stride that won't really be a zero stride causes
a variety of problems with other optimization passes. Those passes don't
know that 0 actually means 1, and they make incorrect assumptions about
sizes written, etc.
The assertion helped catch many bugs in some other work in progress that
tries to store convergent values in SIMD8 registers regardless of the
dispatch width. That code would accidentally generate destination
strides of zero.
v2: Check stride differently depending on register file. Suggested by
Caio.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28256>
v2: Add brw_ir_performance.cpp and brw_fs_generator.cpp changes. Fix
overlapping register allocation (via has_source_and_destination_hazard). Fix
incorrect destination register file encoding.
v3: Prevent lower_regioning from trying to "fix" DPAS sources.
v4: Add instruction latency information for scheduling and perf
estimates.
v5: Remove all mention of DPASW. Suggested by Curro and Caio. Update
the comment in fs_inst::has_source_and_destination_hazard. Suggested
by Caio.
v6: Add some comments near the src2 calculation in
fs_inst::size_read. Suggested by Caio.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25994>
Uses the dispatch_width from the shader (fs_visitor). This was not
possible before because the dispatch_width was not part of
backend_shader.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26323>
This will allow fs_builder have a reference to an fs_visitor (a
"fs_shader" really), instead of a reference to a backend_shader.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26323>
At this point this is more a header dependency due to inline functions,
so shuffle them around. The end goal is to allow fs_builder have a
reference to a fs_visitor (really a fs_shader).
Note the header is still included, a later patch will move the includes
to the call-sites.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26323>
Ahem, "add builder helpers that work on Gfx7"...now might actually work.
Too much copy and paste...
Fixes: 966995d911 ("intel/fs: Add builder helpers for F32TO16/F16TO32 that work on Gfx7.x")
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21974>
These take care of emitting the F32TO16/F16TO32 instructions on Gfx7.x
but otherwise just emit a type converting MOV on Gfx8+.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21783>
When lowering a single instruction with a destination VGRF to 2 or
more, the VGRF is now considered partially written by each generated
instruction and that increases its liveness especially in loops. Thus
potentially increasing the number of spills/fills due to register
allocation.
Putting an UNDEF instruction in front of the lowered instructions
allows the IR to limit the liveness of the VGRF, reducing register
pressure.
This has a pretty dramatic effect on spills/fills for RT shaders. Here
the stats on Q2RTX shaders on DG2 (wipping out any spills/fills due to
register allocation) :
Instructions in all programs: 26150 -> 24955 (-4.6%)
SENDs in all programs: 1148 -> 1148 (+0.0%)
Loops in all programs: 4 -> 4 (+0.0%)
Cycles in all programs: 392179 -> 332787 (-15.1%)
Spills in all programs: 132 -> 116 (-12.1%)
Fills in all programs: 262 -> 154 (-41.2%)
Shader-db results on TGL :
total instructions in shared programs: 21158140 -> 21158377 (<.01%)
instructions in affected programs: 76629 -> 76866 (0.31%)
helped: 18
HURT: 20
helped stats (abs) min: 1 max: 60 x̄: 18.89 x̃: 12
helped stats (rel) min: 0.21% max: 3.61% x̄: 1.02% x̃: 0.77%
HURT stats (abs) min: 1 max: 79 x̄: 28.85 x̃: 18
HURT stats (rel) min: 0.04% max: 2.81% x̄: 1.13% x̃: 0.79%
95% mean confidence interval for instructions value: -4.82 17.30
95% mean confidence interval for instructions %-change: -0.34% 0.57%
Inconclusive result (value mean confidence interval includes 0).
total loops in shared programs: 5753 -> 5753 (0.00%)
loops in affected programs: 0 -> 0
helped: 0
HURT: 0
total cycles in shared programs: 798856834 -> 798870688 (<.01%)
cycles in affected programs: 6208395 -> 6222249 (0.22%)
helped: 22
HURT: 17
helped stats (abs) min: 2 max: 8794 x̄: 1438.18 x̃: 782
helped stats (rel) min: 0.05% max: 2.28% x̄: 0.63% x̃: 0.44%
HURT stats (abs) min: 2 max: 19178 x̄: 2676.12 x̃: 1358
HURT stats (rel) min: 0.04% max: 23.49% x̄: 2.25% x̃: 0.71%
95% mean confidence interval for cycles value: -952.19 1662.65
95% mean confidence interval for cycles %-change: -0.64% 1.90%
Inconclusive result (value mean confidence interval includes 0).
total spills in shared programs: 4078 -> 4066 (-0.29%)
spills in affected programs: 40 -> 28 (-30.00%)
helped: 2
HURT: 0
total fills in shared programs: 2856 -> 2832 (-0.84%)
fills in affected programs: 127 -> 103 (-18.90%)
helped: 2
HURT: 0
total sends in shared programs: 998554 -> 998554 (0.00%)
sends in affected programs: 0 -> 0
helped: 0
HURT: 0
LOST: 0
GAINED: 0
Total CPU time (seconds): 2346.06 -> 2304.80 (-1.76%)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18657>
