Two advantages:
* When using NIR_DEBUG=nir_print_xx, will print outcome only if
there is a change
* We can use NIR_PASS(_, ...) instead of NIR_PASS_V, that has
slightly more validation checks.
This includes:
* v3d_nir_lower_image_load_store
* v3d_nir_lower_io
* v3d_nir_lower_line_smooth
* v3d_nir_lower_load_store_bitsize
* v3d_nir_lower_robust_buffer_access
* v3d_nir_lower_scratch
* v3d_nir_lower_txf_ms
As we are here we also simplify some of them by using the
nir_shader_instructions_pass helper.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17609>
Over-estimating latency can cause us to delay the critical paths of
the shader unnecessarily, producing larger QPU programs that take more
time to execute as a result (and it also adds register pressure) so
striking a balance is important. The thread switching model in V3D
is quite effective at hiding latency and usuallly we just need to
hint it to delay TMU instructions a little bit to find the best
compromise for performance.
The new latency numbers have been chosen empirically by testing
V3DV with Sponza and a few UE4 samples.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17451>
Based on empirical testing with Sponza and a few UE4 samples this is
consistently slightly benefitial for performance.
The most likely reason why this helps is that thrsw is probably
already quite effective at hiding latency and we are already trying
to hide latency at NIR scheduling and also via TMU pipelining, so
piling up on this when scheduling QPU typically ends up providing no
benefit at all for latency and is instead possibly preventing us to
unblock critical paths in the shader that depend on the TMU result,
requiring us to execute more cycles to complete the program.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17451>
We can produce slightly better code for these in the backend, so
do that. For this we need to:
1. Fix our implementation of uadd_carry (which wasn't used) to return
an integer instead of a boolean value.
2. Add an implementation of usub_borrow.
Notice these are only used in Vulkan. In GL these instructions are
always unconditionally lowered by the state tracker in GLSL IR so
we never get to see them in the backend.
Shader-db stats from a collection of Vulkan samples:
total instructions in shared programs: 122351 -> 122345 (<.01%)
instructions in affected programs: 196 -> 190 (-3.06%)
helped: 2
HURT: 0
total uniforms in shared programs: 18670 -> 18672 (0.01%)
uniforms in affected programs: 59 -> 61 (3.39%)
helped: 0
HURT: 2
total max-temps in shared programs: 13145 -> 13147 (0.02%)
max-temps in affected programs: 27 -> 29 (7.41%)
helped: 0
HURT: 2
total inst-and-stalls in shared programs: 123052 -> 123046 (<.01%)
inst-and-stalls in affected programs: 197 -> 191 (-3.05%)
helped: 2
HURT: 0
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17372>
The postponed spill is predicated using the condition from the
last write, but this is only correct if the register was only
written once in the TMU sequence, or if it is always written with
the same predication.
While we could try to track whether this is the case or not, it
would make the postponed spill path even more complex than it
already is, so let's just avoid predicating these. We are already
discouraging TMU spilling of registers in the middle of TMU
sequences, so this should not be a very common case.
Cc: mesa-stable
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17201>
If we are spilling a register that is used in the middle of a TMU
sequence, we postpone the spill until the TMU sequence finishes,
at which point we inject the spill and rewrite the original
instruction to write to the new temp.
However, this doesn't work if the register is written multiple
times during the TMU sequence. In that scenario, we need to ensure
that all writes are rewritten to use the new temp, not just the last
one.
Cc: mesa-stable
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17201>
This is not safe because it may skip regenerating the flags for the
loop condition in the loop continue block and these flags may be
stomped in the loop body by other conditionals.
Fixes: 9909fe6ba ('broadcom/compiler: Skip bool_to_cond where possible')
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17020>
If the sample mask is being written it means we want to discard some of the
samples generated so we should not be promoting the fragment shader to
do early tests, since that would not take into account the sample mask
written from the shader.
Fixes:
dEQP-VK.fragment_operations.early_fragment.sample_count_early_fragment_tests_depth_samples_4
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16626>
This controls the whole lowering of "make tex ops with implicit
derivatives on non-implicit-derivative stages be tex ops with an explicit
lod of 0 instead", but it's really hard to describe that in a git commit
summary.
All existing callers get it added except:
- nir_to_tgsi which didn't want it.
- nouveau, which didn't want it (fixes regressions in shadowcube and
shadow2darray with NIR, since the shading languages don't expose txl of
those sampler types and thus it's not supported in HW)
- optional lowering passes in mesa/st (lower_rect, YUV lowering, etc)
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16156>
We have been reconstructing/rematerializing uniforms for a while, but we
can do this in more scenarios, namely instructions which result is
immutable along the execution of a shader across all channels.
By doing this we gain the capacity to eliminate TMU spills which not
only are slower, but can also make us drop to a fallback compilation
strategy.
Shader-db results show a small increase in instruction counts caused
by us now being able to choose preferential compiler strategies that
are intended to reduce TMU latency. In some cases, we are now also
able to avoid dropping thread counts:
total instructions in shared programs: 12658092 -> 12659245 (<.01%)
instructions in affected programs: 75812 -> 76965 (1.52%)
helped: 55
HURT: 107
total threads in shared programs: 416286 -> 416412 (0.03%)
threads in affected programs: 126 -> 252 (100.00%)
helped: 63
HURT: 0
total uniforms in shared programs: 3716916 -> 3716396 (-0.01%)
uniforms in affected programs: 19327 -> 18807 (-2.69%)
helped: 94
HURT: 50
total max-temps in shared programs: 2161796 -> 2161578 (-0.01%)
max-temps in affected programs: 3961 -> 3743 (-5.50%)
helped: 80
HURT: 24
total spills in shared programs: 3274 -> 3266 (-0.24%)
spills in affected programs: 98 -> 90 (-8.16%)
helped: 6
HURT: 0
total fills in shared programs: 4657 -> 4642 (-0.32%)
fills in affected programs: 130 -> 115 (-11.54%)
helped: 6
HURT: 0
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15710>
This ensures that any channels used for helper invocations are
also spilled/filled correctly.
Alternatively, we could recursively track all temps that get
involved in computing values that are then used in explicit
(dfdx,dfdy) or implicit (texture coordinates for mipmap or
anisotropic filtering, etc) derivatives, and only enable
per-quad on these (or disable spilling of any of these
values).
Fixes:
dEQP-VK.graphicsfuzz.cov-dfdx-dfdy-after-nested-loops
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15705>
We handle uniforms by copying them into the uniform stream to be
consumed with ldunif when they have a constant offset. Otherwise
we fallback to general TMU access, which has more latency.
However, just like we did for UBOs and read-only SSBOs, we can
also try to use the unifa mechanism to handle indirect accesses
in certain cases instead of the TMU fallback.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15575>
Inline uniform blocks store their contents in pool memory rather
than a separate buffer, and are intended to provide a way in which
some platforms may provide more efficient access to the uniform
data, similar to push constants but with more flexible size
constraints.
We implement these in a similar way as push constants: for constant
access we copy the data in the uniform stream (using the new
QUNIFORM_UNIFORM_UBO_*) enums to identify the inline buffer from
which we need to copy and for indirect access we fallback to
regular UBO access.
Because at NIR level there is no distinction between inline and
regular UBOs and the compiler isn't aware of Vulkan descriptor
sets, we use the UBO index on UBO load intrinsics to identify
inline UBOs, just like we do for push constants. Particularly,
we reserve indices 1..MAX_INLINE_UNIFORM_BUFFERS for this,
however, unlike push constants, inline buffers are accessed
through descriptor sets, and therefore we need to make sure
they are located in the first slots of the UBO descriptor map.
This means we store them in the first MAX_INLINE_UNIFORM_BUFFERS
slots of the map, with regular UBOs always coming after these
slots.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15575>
In addition to use the helper, we also remove some of the lowering we
had at preprocess_nir, as they are called now by the helper.
As we are here we also move the call to nir_lower_sysvals_to_varyings,
that for some reason we were calling it before preprocess_nir.
It is worth to note that with this change we lose the ability to debug
the NIR just after spirv_to_nir using V3D_DEBUG, as now this is done
on vk_spirv_to_nir, and as mentioned that includes several lowerings
now. The workaround to that is to use NIR_DEBUG.
We also needed to change how to check the entrypoint on the broadcom
compiler, checking just if it is an entrypoint, instead of assuming
that the name will be "main".
v2: tweak comment, squash v3dv and compiler change (Iago)
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15449>
We have twice the registers in this case so it makes sense to double
this as well. While this causes slight regressions in shader-db
stats (due to additional register pressure), it helps us hide latency
of memory reads better on 2-thread compiles, where the thread switch
mechanism will be less effective. This shows a ~3% performance
improvement on the UE4 SunTemple demo.
total instructions in shared programs: 12642413 -> 12656164 (0.11%)
instructions in affected programs: 2272652 -> 2286403 (0.61%)
helped: 2924
HURT: 3389
total uniforms in shared programs: 3703861 -> 3704776 (0.02%)
uniforms in affected programs: 213729 -> 214644 (0.43%)
helped: 823
HURT: 1272
total max-temps in shared programs: 2150686 -> 2153505 (0.13%)
max-temps in affected programs: 191332 -> 194151 (1.47%)
helped: 1900
HURT: 1891
total spills in shared programs: 3255 -> 3274 (0.58%)
spills in affected programs: 166 -> 185 (11.45%)
helped: 3
HURT: 6
total fills in shared programs: 4630 -> 4656 (0.56%)
fills in affected programs: 367 -> 393 (7.08%)
helped: 7
HURT: 15
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15276>
This can add quite a bit of register pressure so it makes sense to disable it
to prevent us from dropping to 2 threads or increase spills:
total instructions in shared programs: 12672813 -> 12642413 (-0.24%)
instructions in affected programs: 256721 -> 226321 (-11.84%)
helped: 719
HURT: 77
total threads in shared programs: 415534 -> 416322 (0.19%)
threads in affected programs: 788 -> 1576 (100.00%)
helped: 394
HURT: 0
total uniforms in shared programs: 3711370 -> 3703861 (-0.20%)
uniforms in affected programs: 28859 -> 21350 (-26.02%)
helped: 204
HURT: 455
total max-temps in shared programs: 2159439 -> 2150686 (-0.41%)
max-temps in affected programs: 32945 -> 24192 (-26.57%)
helped: 585
HURT: 47
total spills in shared programs: 5966 -> 3255 (-45.44%)
spills in affected programs: 2933 -> 222 (-92.43%)
helped: 192
HURT: 4
total fills in shared programs: 9328 -> 4630 (-50.36%)
fills in affected programs: 5184 -> 486 (-90.62%)
helped: 196
HURT: 0
Compared to the stats before adding scheduling of non-filtered
memory reads we see we that we have now gotten back all that was
lost and then some:
total instructions in shared programs: 12663186 -> 12642413 (-0.16%)
instructions in affected programs: 2051803 -> 2031030 (-1.01%)
helped: 4885
HURT: 3338
total threads in shared programs: 415870 -> 416322 (0.11%)
threads in affected programs: 896 -> 1348 (50.45%)
helped: 300
HURT: 74
total uniforms in shared programs: 3711629 -> 3703861 (-0.21%)
uniforms in affected programs: 158766 -> 150998 (-4.89%)
helped: 1973
HURT: 499
total max-temps in shared programs: 2138857 -> 2150686 (0.55%)
max-temps in affected programs: 177920 -> 189749 (6.65%)
helped: 2666
HURT: 2035
total spills in shared programs: 3860 -> 3255 (-15.67%)
spills in affected programs: 2653 -> 2048 (-22.80%)
helped: 77
HURT: 21
total fills in shared programs: 5573 -> 4630 (-16.92%)
fills in affected programs: 3839 -> 2896 (-24.56%)
helped: 81
HURT: 15
total sfu-stalls in shared programs: 39583 -> 38154 (-3.61%)
sfu-stalls in affected programs: 8993 -> 7564 (-15.89%)
helped: 1808
HURT: 1038
total nops in shared programs: 324894 -> 323685 (-0.37%)
nops in affected programs: 30362 -> 29153 (-3.98%)
helped: 2513
HURT: 2077
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15276>
We do a few changes over NIR's defaults:
1. Lower delay for texture reads. Empirically, we don't observe any
benefits with delays over 50 and since this delay value is still
used by the scheduler in the "favor register pressure" case it is
benefitial to avoid overestimating it too much.
2. Adjust delay for non-filtered TMU reads to the delay selected for
texture reads.
3. In our case, UBO reads from dynamically uniform addresses don't
use the TMU and have a latency of 1 instruction in the best case
scenario or 4 at worse, so we go with 1 so we don't try to move
this early.
This helps us get back some of what we lost when updating the
default scheduler configuration to add a delay for non-filtered
memory reads:
total instructions in shared programs: 13126587 -> 12671765 (-3.46%)
instructions in affected programs: 3764097 -> 3309275 (-12.08%)
helped: 14664
HURT: 4244
total threads in shared programs: 407208 -> 415522 (2.04%)
threads in affected programs: 8716 -> 17030 (95.39%)
helped: 4224
HURT: 67
total uniforms in shared programs: 3812698 -> 3711224 (-2.66%)
uniforms in affected programs: 335170 -> 233696 (-30.28%)
helped: 2816
HURT: 3551
total max-temps in shared programs: 2318430 -> 2159345 (-6.86%)
max-temps in affected programs: 539991 -> 380906 (-29.46%)
helped: 13173
HURT: 1440
total spills in shared programs: 49086 -> 5966 (-87.85%)
spills in affected programs: 48306 -> 5186 (-89.26%)
helped: 1655
HURT: 28
total fills in shared programs: 55810 -> 9328 (-83.29%)
fills in affected programs: 54821 -> 8339 (-84.79%)
helped: 1659
HURT: 22
LOST: 0
GAINED: 3
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15276>
This has been pending for a long time. It is not very consistent to
add a significant delay for textures and not do it for UBOs, etc
The reason we have not been doing this so far is the accumulated effect
on register pressure for V3D as shown by shader-db results below, but
from the point of view of a generic scheduler it makes sense to do this.
Later patches will address V3D specific issues with register pressure
derived from this by letting the driver control its instruction delay
settings.
total instructions in shared programs: 12662138 -> 13126587 (3.67%)
instructions in affected programs: 1813091 -> 2277540 (25.62%)
helped: 2410
HURT: 10499
total threads in shared programs: 415858 -> 407208 (-2.08%)
threads in affected programs: 17348 -> 8698 (-49.86%)
helped: 8
HURT: 4333
total uniforms in shared programs: 3711483 -> 3812698 (2.73%)
uniforms in affected programs: 128012 -> 229227 (79.07%)
helped: 3474
HURT: 2143
total max-temps in shared programs: 2138763 -> 2318430 (8.40%)
max-temps in affected programs: 318780 -> 498447 (56.36%)
helped: 588
HURT: 11997
total spills in shared programs: 3860 -> 49086 (1171.66%)
spills in affected programs: 709 -> 45935 (6378.84%)
helped: 23
HURT: 1595
total fills in shared programs: 5573 -> 55810 (901.44%)
fills in affected programs: 1067 -> 51304 (4708.25%)
helped: 23
HURT: 1595
LOST: 3
GAINED: 0
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15276>
This doesn't have any significant impact shader-db stats and would
reduce our capacity to hide latency from the loads, so it is probably
undesirable:
total instructions in shared programs: 12663189 -> 12663186 (<.01%)
instructions in affected programs: 4222 -> 4219 (-0.07%)
helped: 9
HURT: 4
total uniforms in shared programs: 3711624 -> 3711629 (<.01%)
uniforms in affected programs: 186 -> 191 (2.69%)
helped: 0
HURT: 2
total max-temps in shared programs: 2138822 -> 2138857 (<.01%)
max-temps in affected programs: 569 -> 604 (6.15%)
helped: 1
HURT: 9
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15276>
Now that we don't sort our nodes we can arrange them so we can
easily translate between nodes and temps without a mapping table,
just applying an offset.
To do this we have a single array of nodes where twe put first the nodes
for accumulators and then the nodes for temps. With this setup we can
ensure that for any given temp T, its node is always T + ACC_COUNT.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15168>
Nodes are allocated in order to registers so initially sorting
was used to ensure that nodes with smaller life ranges would
be assigned first and therefore be more likely to get
accumulators.
However, since d81a6e5f1d now we don't rely on order to make
decisions about accumulators and instead we make policy decisions
based on actual liveness, so sorting is no longer strictly
relevant to this decision.
Furthermore, we are not re-sorting nodes after each spill either,
since that would probably require that we rebuild the interference
graph after each spill (the graph identifies nodes by their index).
Shader-db results show a significant improvement in instruction
counts, due to more optimal accumulator assignments. The reason for
this is that we use a round-robin policy for choosing the next
accumulator to assign. The idea behind this is preventing nearby
temps to be assigned to the same accumulator so that QPU scheduling
is more flexible, but if we sort our nodes, we are basically not
assigning temps in program order any more and the round-robin policy
becomes less effective:
total instructions in shared programs: 13000420 -> 12663189 (-2.59%)
instructions in affected programs: 11791267 -> 11454036 (-2.86%)
helped: 62890
HURT: 19987
total threads in shared programs: 415874 -> 415870 (<.01%)
threads in affected programs: 20 -> 16 (-20.00%)
helped: 2
HURT: 4
total uniforms in shared programs: 3711652 -> 3711624 (<.01%)
uniforms in affected programs: 43430 -> 43402 (-0.06%)
helped: 134
HURT: 173
total max-temps in shared programs: 2144876 -> 2138822 (-0.28%)
max-temps in affected programs: 123334 -> 117280 (-4.91%)
helped: 4112
HURT: 1195
total spills in shared programs: 3870 -> 3860 (-0.26%)
spills in affected programs: 1013 -> 1003 (-0.99%)
helped: 14
HURT: 12
total fills in shared programs: 5560 -> 5573 (0.23%)
fills in affected programs: 1765 -> 1778 (0.74%)
helped: 14
HURT: 17
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15168>
For us they are basically uniforms too so we want to make their
lifespans short to facilitate allocating them to accumulators.
total instructions in shared programs: 13043585 -> 13015385 (-0.22%)
instructions in affected programs: 8326040 -> 8297840 (-0.34%)
helped: 24939
HURT: 19894
total threads in shared programs: 415860 -> 415858 (<.01%)
threads in affected programs: 4 -> 2 (-50.00%)
helped: 0
HURT: 1
total uniforms in shared programs: 3721953 -> 3720451 (-0.04%)
uniforms in affected programs: 96134 -> 94632 (-1.56%)
helped: 744
HURT: 435
total max-temps in shared programs: 2173431 -> 2154260 (-0.88%)
max-temps in affected programs: 264598 -> 245427 (-7.25%)
helped: 10858
HURT: 841
total spills in shared programs: 4005 -> 4010 (0.12%)
spills in affected programs: 700 -> 705 (0.71%)
helped: 5
HURT: 10
total fills in shared programs: 5801 -> 5817 (0.28%)
fills in affected programs: 1346 -> 1362 (1.19%)
helped: 6
HURT: 11
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15168>
If we are compiling with a strategy that does not allow TMU spills
we should not allow spilling anything that is not a uniform.
Otherwise the RA cost/benefit algorithm may choose to spill a
temp that is not uniform and that will cause us to immediately
fail the strategy and fallback to the next one, even if we
could've instead chosen to spill more uniforms to compile the
program successfully with that strategy.
Some relevant shader-db stats:
total instructions in shared programs: 13040711 -> 13043585 (0.02%)
instructions in affected programs: 234238 -> 237112 (1.23%)
helped: 73
HURT: 172
total threads in shared programs: 415664 -> 415860 (0.05%)
threads in affected programs: 196 -> 392 (100.00%)
helped: 98
HURT: 0
total uniforms in shared programs: 3717266 -> 3721953 (0.13%)
uniforms in affected programs: 12831 -> 17518 (36.53%)
helped: 6
HURT: 100
total max-temps in shared programs: 2174177 -> 2173431 (-0.03%)
max-temps in affected programs: 4597 -> 3851 (-16.23%)
helped: 79
HURT: 21
total spills in shared programs: 4010 -> 4005 (-0.12%)
spills in affected programs: 55 -> 50 (-9.09%)
helped: 5
HURT: 0
total fills in shared programs: 5820 -> 5801 (-0.33%)
fills in affected programs: 186 -> 167 (-10.22%)
helped: 5
HURT: 0
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15168>
Our cost was 5 which matches the number of instructions we have to
add for a TMU spill (a fill is 4 instructions).
Uniform spills on the other hand add an extra instruction for each
fill and remove one instruction for the spill itself. These have
a cost of 1.
Therefore, if we have a single spill+fill, we end up with +9
instructions if it is a TMU spill and +0 instructions with a uniform
spill, so making the former only 5 times more costly is probably
not a good idea, and this is without even considering the added
latency of the TMU accesses.
Relevant shader-db changes show this causes as a marginal instruction
count increase in a few shaders but better thread counts and lower
TMU spilling overall:
total instructions in shared programs: 13037315 -> 13040711 (0.03%)
instructions in affected programs: 370106 -> 373502 (0.92%)
helped: 187
HURT: 321
total threads in shared programs: 415090 -> 415664 (0.14%)
threads in affected programs: 574 -> 1148 (100.00%)
helped: 287
HURT: 0
total uniforms in shared programs: 3706674 -> 3717266 (0.29%)
uniforms in affected programs: 63075 -> 73667 (16.79%)
helped: 40
HURT: 395
total max-temps in shared programs: 2176080 -> 2174177 (-0.09%)
max-temps in affected programs: 15838 -> 13935 (-12.02%)
helped: 316
HURT: 34
total spills in shared programs: 4247 -> 4010 (-5.58%)
spills in affected programs: 2599 -> 2362 (-9.12%)
helped: 107
HURT: 14
total fills in shared programs: 6121 -> 5820 (-4.92%)
fills in affected programs: 3622 -> 3321 (-8.31%)
helped: 108
HURT: 13
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15168>
On V3D the quality of the code we generate is significantly affected by
how we decide to assign accumulators during register allocation, which
is determined by liveness, favoring short-lived temps.
There are many shaders that end up doing a whole lot of uniform loads
first, and using them later, which is very inconvenient for our register
allocation process because this increases uniform liveness and causes
us to use accumulators less efficientely, leading to significant churn.
To fix this, we move uniforms right before their first use in the same
block, but we need to do this after NIR scheduling, which means we are
doing it in non-SSA form, since the scheduler has a tendency to undo
this optimization and it is not easy to modify it to avoid it, since it
works in more abstract terms, using instruction dependencies, estimated
register pressure and instruction delay information to do its work,
which are very different concepts.
total instructions in shared programs: 13316738 -> 13033613 (-2.13%)
instructions in affected programs: 10389172 -> 10106047 (-2.73%)
helped: 55442
HURT: 16144
total threads in shared programs: 413722 -> 415048 (0.32%)
threads in affected programs: 1428 -> 2754 (92.86%)
helped: 680
HURT: 17
total loops in shared programs: 1716 -> 1690 (-1.52%)
loops in affected programs: 26 -> 0
helped: 26
HURT: 0
total uniforms in shared programs: 3704313 -> 3705181 (0.02%)
uniforms in affected programs: 687730 -> 688598 (0.13%)
helped: 2920
HURT: 7384
total max-temps in shared programs: 2364785 -> 2175190 (-8.02%)
max-temps in affected programs: 1215387 -> 1025792 (-15.60%)
helped: 49667
HURT: 1556
total spills in shared programs: 4241 -> 4248 (0.17%)
spills in affected programs: 642 -> 649 (1.09%)
helped: 11
HURT: 19
total fills in shared programs: 6115 -> 6125 (0.16%)
fills in affected programs: 1276 -> 1286 (0.78%)
helped: 11
HURT: 21
total sfu-stalls in shared programs: 34381 -> 36578 (6.39%)
sfu-stalls in affected programs: 16055 -> 18252 (13.68%)
helped: 3647
HURT: 5206
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15056>
If we have a postponed spill, the temp we create at ip is no longer
the spilled temp and therefore is affected by the thrsw injection.
Fixes corruption in the additive blending animation demo from
Three.js.
Fixes: f3c3228522 ('broadcom/compiler: do not rebuild the interference graph after each spill')
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15112>
When we spill we add new temps. We should be careful not to access
liveness for these until we have re-computed it after all spills and
fill for that the spilled temp have been processed so as to avoid
out-of-bounds accesses to the c->temp_start and c->temp_end arrays.
This fixes a crash in a Three.js demo when we try to patch register
classes after a TMU spill that was caused because we would incorrectly
try to patch the same temps we had just added for the spill itself,
which is not only unnecessary but also incorrect since we these temps
would not have liveness information available yet and thus would
cause out of bounds accesses.
Fixes: f3c3228522 ('broadcom/compiler: do not rebuild the interference graph after each spill')
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15107>
We added spill_count to handle uniform batch spills, which we no longer do.
What we want now is a way to know if we are spilling registers.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15041>
Instead, we only recompute liveness and we add new nodes and
interferences to the graph manually (we also need to patch
register classes in some cases).
To assist in this process, we also add an ip counter to our
instructions that we also recompute after each spill, which we use
to identify registers that cross thrsw boundries introduced with
TMU spills and fills and adjust their register classes accordingly
(removing their capacity to use accumulators).
This significantly reduces the CPU cost of spills. Using
shaders/closed/gputest/piano/7.shader_test as reference:
Compile time up to the first successful compile strategy in main is
~24s and with this change it is ~11s. With this speed up, we can now
try all 2-thread compile strategies (including the fallback scheduler)
in only ~15s.
A full shader-db run results in:
Total CPU time (seconds): 9904.67 -> 9087.98 (-8.25%)
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15041>
We may be pipelining TMU writes and reads, in which case we can
see both TMUWT and LDTMU at the end of a TMU sequence, so we should
not assume that a TMUWT always terminates a sequence.
Also, we had a bug where we were using inst instead of scan_inst
to check if we find another TMUWT after the curent instruction.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15041>
Instead of whether they are allowed to spill or not. This is more flexible.
Also, while we are not currently enabling spilling on any 4-thread strategies,
should we do that in the future, always prefer a 4-thread compile.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15041>
Until now we would only allow spilling as a last resort in the
last 2 strategies, however, it is possible that in some cases
earlier strategies may produce less spills if we allowed spilling
on them.
Likewise, the fallback scheduler can sometimes produce less spills
than 2 threads with optimizations disabled.
With this change, we start allowing all our 2-thread strategies to
spill, and instead of choosing the first strategy that is successful,
we choose the one that doesn't spill or the one with the least amount
of spilling.
It should be noted that this may incur in a significant increase
of compile times. We will address this in a follow-up patch.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15041>
Alejandro Piñeiro
Iago Toral Quiroga
Erik Faye-Lund
Emma Anholt
Jose Maria Casanova Crespo