Gen9 and Cherryview have the ability to mark texture instructions with
the End-of-thread bit under some conditions, which allows the texture
result to be written to the render target directly, rather than
returning to the EU.
In order to handle overlapping primitives correctly, we have to use the
'sendc' instruction which stalls until other threads potentially writing
to the same locations in the render target are retired. Unfortunately,
this stall happens before the texture is sampled (rather than in
parallel with stall), so for some literal edge cases (like the diagonal
edge between two triangles forming a rectangle) there can be a
performance penalty. As a result, it's probably not a good idea to use
this optimization in general.
I had planned to leave it enabled only for BLORP, where we use rectangle
primitives and are typically clearing/blitting an entire render target
without any overlapping primitives, but I noticed that the optimization
wasn't applied in some normal cases anyway. For example, in the piglit
test tests/shaders/glsl-fs-texture2d-bias.shader_test it is applied to
one BLORP-blit shader but not another due to some kind of mishandling of
register types (the destination register type of the texture operation
is UD while the color source of the render target write is F).
Additionally the instruction scheduler assumed that the combined texture
and render target write operation took 0 cycles, leading to cycle
estimates that are wildly inaccurate. Since the optimization was not
implemented for SIMD32 and our decision whether to use the SIMD32
program is made by comparing the estimated performance with that of the
SIMD16 shader, we wrongly threw out a bunch of SIMD32 programs that are
likely profitable.
total cycles in shared programs: 472807891 -> 473784245 (0.21%)
cycles in affected programs: 108277 -> 1084631 (901.72%)
helped: 0
HURT: 1290
total sends in shared programs: 998955 -> 1000245 (0.13%)
sends in affected programs: 1400 -> 2690 (92.14%)
helped: 0
HURT: 1290
LOST: 0
GAINED: 33
This patch shows no performance changes in Intel's Mesa performance CI.
Given the problems, the lack of evidence that the pass improves
performance, and the fact that the hardware feature was removed from
subsequent GPU generations, I think that the pass is not valuable and
should be removed.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5412>
Move the decision one level up, let brw_compile_*() functions use the
spilling information to decide whether or not a certain width
compilation can spill (passed via run_*() functions).
The min_dispatch_width was used to compare with the dispatch_width and
decide whether "a previous shader is already available, so don't
accept spill".
This is replaced by:
- Not calling run_*() functions if it is know beforehand a smaller width
already spilled -- since the larger width will spill and fail;
- Explicitly passing whether or not a shader is allowed to spill. For
the cases where the smaller width is available and haven't spilled,
the larger width will be compiled but is only useful if it won't
spill.
Moving the decision to this level will be useful later for variable
group size, which is a case where we want all the widths to be allowed
to spill.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5142>
These should be more accurate than the current cycle counts, since
among other things they consider the effect of post-scheduling passes
like the software scoreboard on TGL. In addition it will enable us to
clean up some of the now redundant cycle-count estimation
functionality in the instruction scheduler.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This introduces an analysis pass intended to estimate several
performance statistics of the shader, including cycle count latency
and throughput values, based on static modeling. It has instruction
performance information more comprehensive than the current scheduling
pass for all platforms between Gen4-11, and works on both the FS and
VEC4 back-end.
The most immediate purpose of this pass is to implement a heuristic
meant to determine whether using SIMD32 dispatch for a fragment shader
can be expected to help more than it hurts. In addition this will
allow the effect of passes run after scheduling (e.g. the TGL software
scoreboard pass and the VEC4 dependency control pass) to be visible in
shader-db statistics.
But that isn't the end of the story, other potential applications of
this pass (not part of this MR) I've been playing around with are:
- Implement a similar SIMD16 heuristic allowing the identification of
inefficient SIMD16 fragment shaders.
- Implement similar SIMD16 and SIMD32 heuristics for the compute
shader stage -- Currently compute shader builds always use the
SIMD16 shader if available and never use the SIMD32 shader unless
strictly necessary, which is suboptimal under certain conditions.
- Hook up to the instruction scheduler in order to improve the
accuracy of its timing information.
- Use as heuristic in order to drive the selection of scheduling
modes (Matt was experimenting with that).
- Plug to the TGL software scoreboard pass in order to implement a
more effective SBID token allocation algorithm, since in general
the optimal token allocation depends on the timings of all
instructions in the program.
- Use its bottleneck detection functionality in order to implement a
heuristic computing a more optimal bound for the number of fragment
shader threads executed in parallel (by adjusting the
MaximumNumberofThreadsPerPSD control of 3DSTATE_PS).
As a follow-up I'm planning to submit updated timing information for
Gen12 platforms -- Everything else required to support Gen12 like SWSB
handling is already included in this patch, but there were some IP
concerns regarding the TGL timing parameters since they cannot
currently be obtained with the documentation and hardware which is
publicly available. The timing parameters for any previous Gen7-11
platforms can be obtained by anyone by sampling the timestamp register
using e.g. shader_time, though I have some more convenient
instrumentation coming up.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Add new builtin parameters that are used to keep track of the group
size. This will be used to implement ARB_compute_variable_group_size.
The compiler will use the maximum group size supported to pick a
suitable SIMD variant. A later improvement will be to keep all SIMD
variants (like FS) so the driver can select the best one at dispatch
time.
When variable workgroup size is used, the small workgroup optimization
is disabled as it we can't prove at compile time that the barriers
won't be needed.
Extracted from original i965 patch with additional changes by
Caio Marcelo de Oliveira Filho.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4504>
Avoid looping over all VARYING_SLOT_MAX urb_setup array
entries from genX_upload_sbe. Prepare an array indirection
to the active entries of urb_setup already in the compile
step. On upload only walk the active arrays.
v2: Use uint8_t to store the attribute numbers.
v3: Change loop to build up the array indirection.
v4: Rebase.
v5: Style fix.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/308>
Passing shader_stats to the fs_generator constructor means that the
SIMD8 shader stats from the visitor (such as the scheduler mode) will be
reported out for the SIMD16/SIMD32 versions as well.
As you can see, we are now passing 'shader_stats' and 'stats' to
generate_code(), which is obviously odd looking. Ian rebased and
committed an old patch of mine which added the shader_stats struct on
July 30 in commit dabb5d4bee (i965/fs: Add a shader_stats struct.) and
shortly after on August 12 Jason added the brw_compile_stats struct in
commit 134607760a (intel/compiler: Fill a compiler statistics struct).
I'd like to combine the two, but I'm not sure how. shader_stats is an
input to generate_code() while brw_compile_stats is an output and is
only used by the Vulkan driver. Leave it as is for now...
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4093>
This defines a new BRW_ANALYSIS object which wraps the register
pressure computation code along with its result. For the rationale
see the previous commits converting the liveness and dominance
analysis passes to the IR analysis framework.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This involves wrapping fs_live_variables in a BRW_ANALYSIS object and
hooking it up to invalidate_analysis() so it's properly invalidated.
Seems like a lot of churn but it's fairly straightforward. The
fs_visitor invalidate_ and calculate_live_intervals() methods are no
longer necessary after this change.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This moves the following methods that are currently defined in
fs_visitor (even though they are side products of the liveness
analysis computation) and are already implemented in
brw_fs_live_variables.cpp:
> bool virtual_grf_interferes(int a, int b) const;
> int *virtual_grf_start;
> int *virtual_grf_end;
It makes sense for them to be part of the fs_live_variables object,
because they have the same lifetime as other liveness analysis results
and because this will allow some extra validation to happen wherever
they are accessed in order to make sure that we only ever use
up-to-date liveness analysis results.
This shortens the virtual_grf prefix in order to compensate for the
slightly increased lexical overhead from the live_intervals pointer
dereference.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
The invalidate_analysis() method knows what analysis passes there are
in the back-end and calls their invalidate() method to report changes
in the IR. For the moment it just calls invalidate_live_intervals()
(which will eventually be fully replaced by this function) if anything
changed.
This makes all optimization passes invalidate DEPENDENCY_EVERYTHING,
which is clearly far from ideal -- The dependency classes passed to
invalidate_analysis() will be refined in a future commit.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
brw_fs.h (in particular fs_visitor) is logically a user of the live
variables analysis pass, not the other way around.
brw_fs_live_variables.h requires the definition of some FS IR data
structures to compile, but those can be obtained directly from
brw_ir_fs.h without including brw_fs.h. The dependency of
fs_live_variables on fs_visitor is rather accidental and will be
removed in a future commit, a forward declaration is enough for the
moment.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
FIND_LIVE_CHANNEL was using f1.0-f1.1 as temporary flag register on
Gen7, instead use f0.0-f0.1. In order to avoid collision with the
discard sample mask, move the latter to f1.0-f1.1. This makes room
for keeping track of the sample mask of the second half of SIMD32
programs that use discard.
Note that some MOVs of the sample mask into f1.0 become redundant now
in lower_surface_logical_send() and lower_a64_logical_send().
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>x
Use it instead of hard-coding f0.1 for the sample mask of programs
that use discard. This will make the task easier when we replace f0.1
with another flag register location in order to support discard with
SIMD32 shaders.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This is a less invasive alternative to the workaround documented in
the hardware spec for GEN:BUG:1407528679, which doesn't involve
disabling structured control flow (it's unlikely that switching to
GOTO/JOIN would have actually fixed the problem anyway).
Under some conditions Gen12 hardware can end up executing a BB with
all channels disabled, which will lead to the execution of any NoMask
instructions in it, even though any execution-masked instructions will
be correctly shot down. This may break assumptions of some NoMask
SEND messages whose descriptor depends on data generated by live
invocations of the shader.
This avoids the problem by predicating certain instructions on an ANY
horizontal predicate that makes sure that their execution is omitted
when all channels of the program are disabled. The shader-db impact
of this patch seems to be minimal:
total instructions in shared programs: 17169833 -> 17169913 (0.00%)
instructions in affected programs: 30663 -> 30743 (0.26%)
helped: 0
HURT: 42
total cycles in shared programs: 336966176 -> 336968568 (0.00%)
cycles in affected programs: 2367290 -> 2369682 (0.10%)
helped: 0
HURT: 13
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Cc: 20.0 <mesa-stable@lists.freedesktop.org>
v2: Add a big comment explaining the [IU]SUB_SAT lowering. Suggested by
Caio.
v3: Use get_fpu_lowered_simd_width in get_lowered_simd_width. Suggested
by Ken on IRC.
v4: Fix a typo in a comment. Noticed by Caio.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/767>
This involves permuting the registers of barycentric vectors to have
the standard X[0-n] Y[0-n] layout at NIR translation time.
Barycentrics are converted to the format expected by the PLN
instruction in the lower_barycentrics() pass run after the
optimization loop.
Main reason is correctness of SIMD32 fragment shaders. The
shuffle_from_pln_layout() and shuffle_to_pln_layout() helpers used
during NIR translation are busted for SIMD32. This leads to serious
corruption at present with INTEL_DEBUG=do32, especially on Gen11+
where these helpers are hit more frequently due to the lack of a
hardware PLN instruction.
Of course one could have chosen to fix those helpers instead, but
there is another far more subtle issue that was reported during review
of the SIMD32 fragment shader codegen changes: The SIMD splitting pass
currently handles SIMD32 barycentric vectors as if they had the
standard X[0-n] Y[0-n] layout, even though they are interleaved for
the PLN instruction, which causes incorrect execution masks to be
applied to the MOVs unzipping barycentric vectors in cases where a
LINTERP instruction occurs under non-uniform control flow.
I'm not aware of any conformance regressions due to the latter issue
at present, but for our peace of mind let's move the conversion to the
PLN layout into the lower_barycentrics() pass run after
lower_simd_width().
This leads to the following shader-db improvements (including SIMD32
shaders) in combination with the previous back-end preparation changes
-- Without them (especially the copy propagation changes) this would
lead to a massive number of regressions. On ICL:
total instructions in shared programs: 20662316 -> 20466903 (-0.95%)
instructions in affected programs: 10538474 -> 10343061 (-1.85%)
helped: 68775
HURT: 6
total spills in shared programs: 8938 -> 8748 (-2.13%)
spills in affected programs: 376 -> 186 (-50.53%)
helped: 9
HURT: 5
total fills in shared programs: 8965 -> 8663 (-3.37%)
fills in affected programs: 965 -> 663 (-31.30%)
helped: 9
HURT: 6
LOST: 146
GAINED: 43
On SKL:
total instructions in shared programs: 18725867 -> 18614912 (-0.59%)
instructions in affected programs: 3876590 -> 3765635 (-2.86%)
helped: 27492
HURT: 2
LOST: 191
GAINED: 417
On SNB:
total instructions in shared programs: 14573613 -> 13980646 (-4.07%)
instructions in affected programs: 5199074 -> 4606107 (-11.41%)
helped: 29998
HURT: 0
LOST: 21
GAINED: 30
Results are somewhat less impressive but still significant without
SIMD32 fragment shaders enabled. On ICL:
total instructions in shared programs: 16148728 -> 16061659 (-0.54%)
instructions in affected programs: 6114788 -> 6027719 (-1.42%)
helped: 42046
HURT: 6
total spills in shared programs: 8218 -> 8028 (-2.31%)
spills in affected programs: 376 -> 186 (-50.53%)
helped: 9
HURT: 5
total fills in shared programs: 8953 -> 8651 (-3.37%)
fills in affected programs: 965 -> 663 (-31.30%)
helped: 9
HURT: 6
LOST: 0
GAINED: 3
On SKL:
total instructions in shared programs: 14927994 -> 14926738 (-0.01%)
instructions in affected programs: 168850 -> 167594 (-0.74%)
helped: 711
HURT: 2
On SNB:
total instructions in shared programs: 10770538 -> 10734403 (-0.34%)
instructions in affected programs: 2702172 -> 2666037 (-1.34%)
helped: 17818
HURT: 0
All of the hurt shaders are either spilling slightly more or emitting
additional NOP instructions due to the SIMD16 POW workaround for
Gen8-9 combined with differences in scheduling.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
The goal is to represent barycentrics with the standard vector layout
during optimization and particularly SIMD lowering. Instead of
emitting the barycentric layout conversions at NIR translation time,
do it later as a lowering pass. For the moment this is only applied
to PI messages, but we'll give the same treatment to LINTERP
instructions too.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
We're about to change the layout of barycentric vectors, which will
involve permuting the GRFs of barycentrics fetched from the thread
payload. Make room for this in a function separate from the generic
fetch_payload_reg(), since the permutation will only be applicable to
barycentric vectors. This allows simplifying fetch_payload_reg(),
since there was no need for handling multiple-component payload
registers except for barycentrics.
This causes some minor shader-db noise due to the new helper emitting
a LOAD_PAYLOAD instruction unconditionally, but it will be cleaned up
shortly.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This will be convenient in a later commit enabling SIMD32 fragment
shaders, and happens to fix the calculation for MATH instructions
which is currently inaccurate for SIMD-lowered instructions on Gen4-5
platforms (all of them on Gen4 in SIMD16 mode), since it was based on
the shader's dispatch width rather than on the actual execution size
of the instruction.
This causes some shader-db noise on Gen4 due to the more compact
register allocation interacting with the SEND dependency workarounds,
but otherwise no major changes.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
The liveness calculation done by the local CSE pass in order to prune
AEB entries whose sources are no longer live is currently inaccurate,
because the live intervals are calculated once at the beginning of the
pass, so they don't take into account any of the copy instructions
inserted by the CSE pass as it makes progress. However the IP counter
used in that calculation is based on the start_ip of the basic block,
which is updated automatically whenever any instructions are inserted
into the CFG. This causes the IP counter and liveness intervals to
get out of sync in programs with multiple basic blocks, causing the
CSE pass to toss AEB entries prematurely, which can lead to missed
optimization opportunities rather non-deterministically.
On BDW this leads to the following shader-db changes:
total instructions in shared programs: 14952488 -> 14951763 (-0.00%)
instructions in affected programs: 45416 -> 44691 (-1.60%)
helped: 40
HURT: 4
total spills in shared programs: 20989 -> 20970 (-0.09%)
spills in affected programs: 103 -> 84 (-18.45%)
helped: 3
HURT: 0
total fills in shared programs: 24981 -> 24926 (-0.22%)
fills in affected programs: 127 -> 72 (-43.31%)
helped: 3
HURT: 0
In addition it avoids a number of regressions in combination with some
of the optimization changes I'm working on for SIMD32, which would
have made CSE more effective... Causing it to be less effective
elsewhere in the program astonishingly.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This reverts commit 52c7df1643. The pass,
while clearly useful for some shaders, has at least three bugs that I
was able to find fairly quickly:
1. It doesn't work for type-converting MOVs because f > 0 is not the
same as f2i(f) > 0
2. CSEL is a 3src instruction and only supports one source type; it
doesn't take this into account and tries to create instructions
which do a F compare and a D select. This is especially nasty to
debug because you don't see that in the dumped assembly because we
don't properly assert that types are the same in codegen.
3. While you can handle 2, in theory, by reinterpreting types, you
can't do that in the presence of source modifiers. This pass
doesn't even attempt to detect that.
Those are just the ones I found with the one almost trival shader I was
debugging. There very likely may be more and. Best thing to do for now
is just shut it off until someone has the time to figure out how to do
this properly and write tests to ensure it's correct.
Fixes: 3cb085e6d61a "i965/fs: Merge CMP and SEL into CSEL on Gen8+"
Reviewed-by: Brian Paul <brianp@vmware.com>
This commit fills in a number of different pieces:
1. We add support to brw_nir_lower_mem_access_bit_sizes to handle the
new intrinsics. This involves simple plumbing work as well as a
tiny bit of extra logic to always scalarize scratch intrinsics
2. Add code to brw_fs_nir.cpp to turn nir_load/store_scratch intrinsics
into byte/dword scattered read/write messages which use the A32
stateless model.
3. Add code to lower_surface_logical_send to handle dword scattered
messages and the A32 stateless model.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Gen12+ hardware lacks the register scoreboard logic that used to
guarantee data coherency between register reads and writes in previous
generations. This lowering pass runs after register allocation in
order to make up for it.
It works by performing global dataflow analysis in order to determine
the set of potential dependencies of every instruction in the shader,
and then inserts any required SWSB annotations and additional SYNC
instructions in order to guarantee data coherency.
v2: Drop unnecessary _safe list iteration (Caio).
v3: Temporarily workaround potential WaR hazard between FPU
instruction and subsequent out-of-order write, pending
clarification from the hardware team. Drop redundant tracking of
implicit access of acc0-1, since the hardware guarantees coherency
of these (but not the other accumulators...).
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
We need this function to emit code that setups the control register
later with the defined execution mode for the shader. Therefore, we
emit it as the first instruction.
v2:
- Fix bug in setting the default mode mask in brw_rnd_mode_from_nir().
- Fix support for rounding modes in brw_rnd_mode_from_nir().
v3:
- Updated to renamed shader info member and enum values (Andres).
v4:
- Add actual emission as first instruction of emit_nir_code (Caio).
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Signed-off-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
It's not used by anything anymore now that so much lowering has been
moved into NIR. Sadly, we still need on in brw_compile_gs() for
geometry shaders on Sandy Bridge. Short of a lot of pointless work,
that one's probably not going away.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is all annoying plumbing work which just adds support for a
new brw_compile_stats struct. This struct provides a binary driver
readable form of the same statistics we dump out to stderr when we
INTEL_DEBUG is set with a shader stage.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
While NIR's lower_imul64() solves the case of 64 bit integer multiplications
generated early, we don't have a way to lower such instructions when they are
generated by our own backend, such as the scan/reduce intrinsics. We'll need
this soon, so implement it now.
An easy way to test this is to simply disable nir_lower_imul64 to let
those operations reach the backend.
v2:
- Fix Q/UQ copy/paste errors (Caio).
- Transform an 'if' into 'else if' (Caio).
- Add an extra comment to clarify the need for 64b = 32b * 32b
(Caio).
- Make private functions private (Caio).
v3:
- Remove ambiguity with 'b' and 'd' variables (Caio).
- Allocate potentially less regs for the dwords (Caio).
Cc: Jason Ekstrand <jason.ekstrand@intel.com>
Cc: Matt Turner <matt.turner@intel.com>
Cc: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Don't instantiate a builder for each instruction during
lower_integer_multiplication(). Instantiate one only when needed.
On the other hand, these unneeded builders don't seem to cost much to
init, so I don't expect any significant difference in performance:
this is mostly about code organization.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
The lower_integer_multiplication() function is already a little too
big. I want to add more to it, so let's reorganize the existing code
first. Let's start with just extracting the current code to
subfunctions. Later we'll change them a little more.
v2: Make private functions private (Caio).
v3: Fix typo (Caio).
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
It'll grow further, and we'd like to avoid adding an additional
parameter to fs_generator() for each new piece of data.
v2 (idr): Rebase on 17 months. Track a visitor instead of a cfg.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This allows us to drop legacy userclip plane handling in both the vec4
and FS backends, and simplifies a few interfaces.
v2 (Jason Ekstrand):
- Move brw_nir_lower_legacy_clipping to brw_nir_uniforms.cpp because
it's i965-specific.
- Handle adding the params in brw_nir_lower_legacy_clipping
- Call brw_nir_lower_legacy_clipping from brw_codegen_vs_prog
Co-authored-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Right now, all keys have two things in common: a program string ID and a
sampler_prog_key_data. I'd like to add another thing or two and need a
place to put it. This commit adds a new brw_base_prog_key struct which
contains those two common bits.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This is the same as the need_dest parameter to
prepare_alu_destination_and_sources. This allows us to not change the
register that is expected to hold an result if an instruction is
re-emitted. This is particularly a problem if the re-emitted
instruction is a partial write. A later patch will use this feature.
No shader-db changes on any Intel platform.
v2: Don't do the Boolean resolve when there is no destination. If the
ALU instruction didn't write a register, there's nothing to resolve.
This replaces an earlier patch "intel/fs: Allocate dummy destination
register when need_dest is false".
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Our tessellation control shaders can be dispatched in several modes.
- SINGLE_PATCH (Gen7+) processes a single patch per thread, with each
channel corresponding to a different patch vertex. PATCHLIST_N will
launch (N / 8) threads. If N is less than 8, some channels will be
disabled, leaving some untapped hardware capabilities. Conditionals
based on gl_InvocationID are non-uniform, which means that they'll
often have to execute both paths. However, if there are fewer than
8 vertices, all invocations will happen within a single thread, so
barriers can become no-ops, which is nice. We also burn a maximum
of 4 registers for ICP handles, so we can compile without regard for
the value of N. It also works in all cases.
- DUAL_PATCH mode processes up to two patches at a time, where the first
four channels come from patch 1, and the second group of four come
from patch 2. This tries to provide better EU utilization for small
patches (N <= 4). It cannot be used in all cases.
- 8_PATCH mode processes 8 patches at a time, with a thread launched per
vertex in the patch. Each channel corresponds to the same vertex, but
in each of the 8 patches. This utilizes all channels even for small
patches. It also makes conditions on gl_InvocationID uniform, leading
to proper jumps. Barriers, unfortunately, become real. Worse, for
PATCHLIST_N, the thread payload burns N registers for ICP handles.
This can burn up to 32 registers, or 1/4 of our register file, for
URB handles. For Vulkan (and DX), we know the number of vertices at
compile time, so we can limit the amount of waste. In GL, the patch
dimension is dynamic state, so we either would have to waste all 32
(not reasonable) or guess (badly) and recompile. This is unfortunate.
Because we can only spawn 16 thread instances, we can only use this
mode for PATCHLIST_16 and smaller. The rest must use SINGLE_PATCH.
This patch implements the new 8_PATCH TCS mode, but leaves us using
SINGLE_PATCH by default. A new INTEL_DEBUG=tcs8 flag will switch to
using 8_PATCH mode for testing and benchmarking purposes. We may
want to consider using 8_PATCH mode in Vulkan in some cases.
The data I've seen shows that 8_PATCH mode can be more efficient in
some cases, but SINGLE_PATCH mode (the one we use today) is faster
in other cases. Ultimately, the TES matters much more than the TCS
for performance, so the decision may not matter much.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
