This helps a lot with accessing surface handles in control flow. Our
resource_intel intrinsic has a non_uniform flag, in which case we
cannot apply this optimization. But in uniform cases, this is just a
massive win. We drop all kind of pipeline stalls due to
find_live_channel. We also reduce register pressure by doing the
surface handle computation in a single GRF (instead of 2 or 4).
There are some regressions in max dispatch width but those I think are
only on SIMD32 and due to the current heuristic disabling it after
throughput comparison with SIMD16. We know this heuristic is not
perfect, it should probably be updated in another change.
Here are some stats (all titles seem to have similar gains) :
PERCENTAGE DELTAS Shaders Instrs Cycles Subgroup size Send messages Spill count Fill count Scratch Memory Size Max live registers Max dispatch width
red_dead_redemption2 5860 -36.80% -5.67% +0.77% +0.06% -81.26% -79.16% -70.62% -8.63% -6.93%
---------------------------------------------------------------------------------------------------------------------------------------------------------------
All affected 4716 -37.29% -5.67% +0.95% +0.07% -81.26% -79.16% -70.62% -9.15% -8.47%
---------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 5860 -36.80% -5.67% +0.77% +0.06% -81.26% -79.16% -70.62% -8.63% -6.93%
PERCENTAGE DELTAS Shaders Instrs Cycles Subgroup size Send messages Spill count Fill count Scratch Memory Size Max live registers Max dispatch width
rise_of_the_tomb_raider_g2 12010 -37.19% -22.12% +0.01% +0.00% -99.01% -99.14% -98.65% -7.62% -4.96%
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
All affected 11732 -37.27% -22.14% +0.01% +0.00% -99.01% -99.14% -98.65% -7.67% -5.11%
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 12010 -37.19% -22.12% +0.01% +0.00% -99.01% -99.14% -98.65% -7.62% -4.96%
PERCENTAGE DELTAS Shaders Instrs Cycles Spill count Fill count Scratch Memory Size Max live registers Max dispatch width
total_war_warhammer2 462 -27.45% -12.42% -82.35% -88.46% -66.67% -5.52% -5.62%
-----------------------------------------------------------------------------------------------------------------------------------
All affected 335 -28.31% -12.77% -82.35% -88.46% -66.67% -6.25% -7.24%
-----------------------------------------------------------------------------------------------------------------------------------
Total 462 -27.45% -12.42% -82.35% -88.46% -66.67% -5.52% -5.62%
PERCENTAGE DELTAS Shaders Instrs Cycles Subgroup size Send messages Spill count Fill count Scratch Memory Size Max live registers Max dispatch width
witcher_3_dxvk_g2 1049 -36.94% -57.82% +0.06% +0.01% -98.52% -97.29% -98.10% -7.81% -1.00%
------------------------------------------------------------------------------------------------------------------------------------------------------------
All affected 693 -41.93% -58.45% +0.09% +0.01% -98.52% -97.29% -98.10% -10.25% -1.33%
------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 1049 -36.94% -57.82% +0.06% +0.01% -98.52% -97.29% -98.10% -7.81% -1.00%
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21645>
Using the information coming from surface_index_intel, we can tell
whether we should use the BTI or bindless heap for a particular SSBO
access.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21645>
nir->info.subgroup_size can be set to an enum :
SUBGROUP_SIZE_VARYING = 0
SUBGROUP_SIZE_UNIFORM = 1
SUBGROUP_SIZE_API_CONSTANT = 2
SUBGROUP_SIZE_FULL_SUBGROUPS = 3
So compute the API subgroup size value and compare it to the dispatch
size to determine whether we need some bound checking.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 9ac192d79d ("intel/fs: bound subgroup invocation read to dispatch size")
Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21856>
This mainly lets the software scoreboarding pass correctly mark the
instructions, without needing to resort to fragile manual handling in
the generator.
We can also make small improvements. On Gfx 8LP-12.0, we no longer have
the restrictions about DWord alignment, so we can simply write each half
into its intended location, rather than writing it to the low DWord and
then shifting it in place.
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 mesh shader is spawned on a different slice than the originating
task shader, then input task urb handle can come from a different
slice, so masking this information off will load data from the current
slice, instead of the one where real data are.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21007>
This new helper, do_emit_fb_writes() does the actual walk over all the
render targets to emit each of the different FB writes. We want this in
a helper because we're about to go a bit crazy with coarse.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21094>
Whenever one of them is BRW_SOMETIMES, we depend on dynamic flag pushed
in as a push constant. In this case, we have to often have to do the
calculation both ways and SEL the result. It's a bit more code but
decouples MSAA from the shader key.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21094>
We can lower FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD into other more
generic sends and drop this internal opcode.
The idea behind this change is to allow bindless surfaces to be used
for UBO pulls and why it's interesting to be able to reuse
setup_surface_descriptors(). But that will come in a later change.
No shader-db changes on TGL & DG2.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20416>
These are handled identically in almost all cases. There is one place
in the legacy surface lowering that was obtaining the bitsize from the
opcode, but the LSC-based lowering uses (type_sz(inst->dst.type) * 8)
for that and works just fine. If we just do that in the legacy lowering
too, then we don't need this plethora of opcodes.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20604>
These are basically identical save for:
- shared has surface hardcoded to SLM rather than an SSBO index
- shared has to handle adding the 'base' const_index (SSBO have none)
- the NIR source index for data is shifted by one
It's not worth copy and pasting the entire function for this.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20604>
These are now basically identical to their non-float counterparts. The
only thing that differed was the opcode checking to determine which
operands existed. Now that we have a unified opcode enum and a helper
for the number of data operands, we can just use that.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20604>
There's no need to pass both the intrinsic and an opcode computed from
that same intrinsic. Just do it in the functions themselves.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20604>
The first instruction of any kernel should have non-zero emask. This
restriction needs to be obeyed to avoid GPU hangs.
Patch adds a function to insert dummy mov as first instruction
to make sure this requirement is fulfilled.
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20194>
There will be situations where we will want to use a local builder
rather than the one associated with NIR->backend translation.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16970>
VS, TCS, TES, and GS threads must end with a URB write message with the
EOT (end of thread) bit set. For VS and TES, we shadow output variables
with temporaries and perform all stores at the end of the shader, giving
us an existing message to do the EOT.
In tessellation control shaders, we don't defer output stores until the
end of the thread like we do for vertex or evaluation shaders. We just
process store_output and store_per_vertex_output intrinsics where they
occur, which may be in control flow. So we can't guarantee that there's
a URB write being at the end of the shader.
Traditionally, we've just emitted a separate URB write to finish TCS
threads, doing a writemasked write to an single patch header DWord.
On Broadwell, we need to set a "TR DS Cache Disable" bit, so this is
a convenient spot to do so. But on other platforms, there's no such
field, and this write is purely wasteful.
Insetad of emitting a separate write, we can just look for an existing
URB write at the end of the program and tag that with EOT, if possible.
We already had code to do this for geometry shaders, so just lift it
into a helper function and reuse it.
No changes in shader-db.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17944>
Move subgroup_id, that's only used by CS for verx10 < 125, as part of
the payload too -- even though is not, strictly speaking.
Note the thread execution of Task/Mesh is similar enough, so we make
their common struct inherit from cs_thread_payload.
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18176>
Move the setup into the FS thread payload constructor. Consolidate
payload setup for that in brw_fs_thread_payload.cpp file.
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18176>
Allow us to implement this in brw_fs_visitor.cpp, which then will
let us deduplicate code between the CS-like barrier and the TCS
barrier in a later patch.
Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18362>
Make it clearer we are dealing with multiple patches,
works better in constrast with SINGLE_PATCH.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18151>
This will make convenient later to keep track of the urb
handles directly in a Task thread payload struct (to be part of
fs_visitor).
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18188>
This backend lowering code has been dead since the removal of i965 -
nothing in the current source tree ever sets the flag.
This is handled by iris_setup_uniforms() and crocus_setup_uniforms().
Variable group size does not appear to be a feature in anv.
Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18055>
Bspec 53421 says:
"A URB fence memory is typically performed prior the thread
exit message, so that the next thread dispatch that reads
that URB memory will see it."
Cc: 22.1 <mesa-stable>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16665>
This allows the software scoreboarding pass, scheduler, and so on
to handle the individual instructions and handle them, rather than
trusting in the generator to do scoreboarding correctly when expanding
the virtual instruction to multiple actual instructions.
By using SHADER_OPCODE_READ_SR_REG, we also correctly handle the
software scoreboarding workaround when reading DMask/VMask.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17530>
While we've taken advantage of split-sends in select situations, there
are many other cases (such as sampler messages, framebuffer writes, and
URB writes) that have never received that treatment, and continued to
use monolithic send payloads.
This commit introduces a new optimization pass which detects SEND
messages with a single payload, finds an adjacent LOAD_PAYLOAD that
produces that payload, splits it two, and updates the SEND to use both
of the new smaller payloads.
In places where we manually used split SENDS, we rely on underlying
knowledge of the message to determine a natural split point. For
example, header and data, or address and value.
In this pass, we instead infer a natural split point by looking at the
source registers. Often times, consecutive LOAD_PAYLOAD sources may
already be grouped together in a contiguous block, such as a texture
coordinate. Then, there is another bit of data, such as a LOD, that
may come from elsewhere. We look for the point where the source list
switches VGRFs, and split it there. (If there is a message header, we
choose to split there, as it will naturally come from elsewhere.)
This not only reduces the payload sizes, alleviating register pressure,
but it means that we may be able to eliminate some payload construction
altogether, if we have a contiguous block already and some extra data
being tacked on to one side or the other.
shader-db results for Icelake are:
total instructions in shared programs: 19602513 -> 19369255 (-1.19%)
instructions in affected programs: 6085404 -> 5852146 (-3.83%)
helped: 23650 / HURT: 15
helped stats (abs) min: 1 max: 1344 x̄: 9.87 x̃: 3
helped stats (rel) min: 0.03% max: 35.71% x̄: 3.78% x̃: 2.15%
HURT stats (abs) min: 1 max: 44 x̄: 7.20 x̃: 2
HURT stats (rel) min: 1.04% max: 20.00% x̄: 4.13% x̃: 2.00%
95% mean confidence interval for instructions value: -10.16 -9.55
95% mean confidence interval for instructions %-change: -3.84% -3.72%
Instructions are helped.
total cycles in shared programs: 848180368 -> 842208063 (-0.70%)
cycles in affected programs: 599931746 -> 593959441 (-1.00%)
helped: 22114 / HURT: 13053
helped stats (abs) min: 1 max: 482486 x̄: 580.94 x̃: 22
helped stats (rel) min: <.01% max: 78.92% x̄: 4.76% x̃: 0.75%
HURT stats (abs) min: 1 max: 94022 x̄: 526.67 x̃: 22
HURT stats (rel) min: <.01% max: 188.99% x̄: 4.52% x̃: 0.61%
95% mean confidence interval for cycles value: -222.87 -116.79
95% mean confidence interval for cycles %-change: -1.44% -1.20%
Cycles are helped.
total spills in shared programs: 8387 -> 6569 (-21.68%)
spills in affected programs: 5110 -> 3292 (-35.58%)
helped: 359 / HURT: 3
total fills in shared programs: 11833 -> 8218 (-30.55%)
fills in affected programs: 8635 -> 5020 (-41.86%)
helped: 358 / HURT: 3
LOST: 1 SIMD16 shader, 659 SIMD32 shaders
GAINED: 65 SIMD16 shaders, 959 SIMD32 shaders
Total CPU time (seconds): 1505.48 -> 1474.08 (-2.09%)
Examining these results: the few shaders where spills/fills increased
were already spilling significantly, and were only slightly hurt. The
applications affected were also helped in countless other shaders, and
other shaders stopped spilling altogether or had 50% reductions. Many
SIMD16 shaders were gained, and overall we gain more SIMD32, though many
close to the register pressure line go back and forth.
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17018>
