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perf(cake_dense_projection_det_gemm): plan the 17408 -> 5120 and 16384 -> 6144 forwards with the row-half-release program at T-exact keys - #8719
This PR changes the Cake dense_projection_det_gemm package in flashinfer.experimental, the deterministic dense projection GEMM. Most programs in the package are BF16-operand GEMMs (forward, dgrad and wgrad), and one is an FP32 router GEMM. The package already ships one program that is built only for sm_107a. It is the half-tail tall program with a column-grouped raster, and its overlapped epilogue releases output by row half. This PR builds the same program from the same kernel source for sm_100a and sm_103a. No kernel source changes, and the number of compiled libraries in the package goes from 273 to 275. The PR plans this row-half-release program at 4 row rules. Each rule applies at a single token count T. Two of these rules already exist and cover the 17408→5120 forward (BF16 output) at T 16231 and 16384 on sm_100a. They used the overlapped half-tail program with the column-grouped raster in 12-column-tile groups. They now select the row-half-release program, still with 12-column-tile raster groups. The two new rules cover the 16384→6144 forward (the o_proj layer, BF16 output) at T 16231, one on sm_100a and one on sm_103a. They use 8-column-tile raster groups. Before this PR, that row used the overlapped half-tail program from the ragged rule. On sm_103a, the 17408→5120 rows keep their current program. The rule count goes from 384 to 386 (sm_100a 152 → 153, sm_103a 107 → 108). The sm_107a rules are unchanged. The baseline is the previous Cake version of the package on main. On GB200, the 17408→5120 rows have a speedup of 1.013 at both T, and the o_proj row measures 1.018. On GB300 the o_proj row measures 1.013. On B200 the 17408→5120 rows measure 1.009 and 1.010, which is a small gain, and the o_proj row measures 1.018. On B300 the o_proj row measures 1.021. No changed row is slower on any of the four GPUs. Every rule keeps the K split of the row's previous plan (whole K per output tile), so outputs on those rows are bitwise identical to main on all four. All other rows of the 294-row shape list plan the same programs as main.
Speedup of this PR over the previous Cake version on main. GB200 (sm_100a, 152 SMs), GB300 (sm_103a, 152 SMs), B200 (sm_100a, 148 SMs), B300 (sm_103a, 148 SMs); CUDA 13.4, cold L2, BF16 output. Speedup = previous time / this PR time, and values above 1 mean this PR is faster.
GPU (arch, SMs)
layer (in→out)
op
out
T
previous µs
this PR µs
speedup
GB200 (sm_100a, 152)
17408→5120
forward
BF16
16231
1634.7
1614.2
1.013
GB200 (sm_100a, 152)
17408→5120
forward
BF16
16384
1638.6
1617.6
1.013
GB200 (sm_100a, 152)
16384→6144 (o_proj)
forward
BF16
16231
1854.3
1822.4
1.018
GB300 (sm_103a, 152)
16384→6144 (o_proj)
forward
BF16
16231
1619.9
1599.8
1.013
B200 (sm_100a, 148)
17408→5120
forward
BF16
16231
1777.3
1761.1
1.009
B200 (sm_100a, 148)
17408→5120
forward
BF16
16384
1780.8
1763.2
1.010
B200 (sm_100a, 148)
16384→6144 (o_proj)
forward
BF16
16231
1989.7
1954.5
1.018
B300 (sm_103a, 148)
16384→6144 (o_proj)
forward
BF16
16231
1750.3
1714.0
1.021
The package also ships FP32-output forms, weight-gradient (wgrad) programs and the FP32 router GEMM (run through BF16x3 emulation), on sm_100a, sm_103a and sm_107a.
Summary by CodeRabbit
Performance Improvements
Updated dense-projection execution for select large-input workloads on supported GPUs. These workloads now use tuned computation paths for specific input and output sizes, including cases with 16K-token inputs. Other tested shapes retain their existing behavior.
…4 -> 6144 forwards with the row-half-release program at T-exact keys
The row-half-release form of the half-tail tall program with the
column-grouped raster (dense_proj_det_gemm_kk_n256_m256_ht_cg_or_pro7,
the overlapped tall epilogue released by row half) ships for sm_107a
only. This change builds the same program for sm_100a and sm_103a and
plans it at T-exact keys there:
- the registry record gains sm_100a and sm_103a, and build.json two
entries built from the same two sources with the same definitions
(275 libraries); no source file changes;
- the 17408 -> 5120 forward at T 16231 / 16384 on sm_100a (2 keys,
12-column-tile raster groups) moves from the column-chunk overlapped
program to this one; the sm_103a keys keep the column-chunk program;
- the 16384 -> 6144 forward at T 16231 gains a key on sm_100a and on
sm_103a (8-column-tile raster groups) in place of the ragged rule's
overlapped half-tail program.
Each key keeps the per-tile K partitions of the row's plan without it
(whole K per output tile), so every output is bitwise equal to that
plan's; every other T and sm_107a are unchanged; the rule count goes
from 384 to 386.
Latency (us, previous plan -> this plan; cold L2, CUDA 13.4,
median of order-balanced passes; 0 slower passes on any board):
row GB200 (sm_100a) B200 (sm_100a)
17408 -> 5120 T16231 1634.7 -> 1614.2 1777.3 -> 1761.1
17408 -> 5120 T16384 1638.6 -> 1617.6 1780.8 -> 1763.2
16384 -> 6144 T16231 1854.3 -> 1822.4 1989.7 -> 1954.5
row GB300 (sm_103a) B300 (sm_103a)
16384 -> 6144 T16231 1619.9 -> 1599.8 1750.3 -> 1714.0
Tests: the rule counts, the measured-rows table, and the GB T-exact
table (planner test: program, raster group, the K partitions of the
plan without the key, T +- 1 unchanged; device test: FP64 reference and
bitwise equality with the plan without the key); the round-24 planner
tests read the sm_100a 16384 -> 6144 forward at T 16231 through the new
key (rule test) or without it (ovr knob test).
@flashinfer-bot run tests/experimental/test_cake_dense_projection_det_gemm.py tests/experimental/test_cake_dense_projection_det_gemm_names.py tests/experimental/test_cake_dense_projection_gemm.py
This change registers row-half-release dense-projection GEMM templates for sm_100a and sm_103a. It adds or updates exact-shape rules for selected forward cases and adjusts planner and measured-shape tests.
The kernel maps and module record register the template for sm_100a and sm_103a. The AOT manifest adds a library entry for each architecture.
Update exact-shape selection and validation flashinfer/experimental/dense_projection_det_gemm/cake_backend.py, flashinfer/experimental/dense_projection_det_gemm/README.md, tests/experimental/test_cake_dense_projection_det_gemm.py
Rules select the row-half-release program for specified shapes and token counts. Documentation and tests reflect the updated rules and planner behavior.
flashinfer-ai/flashinfer#6596: The tracker lists this PR as a progress item for the same dense-projection GEMM family.
flashinfer-ai/flashinfer#7233: The issue audits the same package’s build manifest and exact-shape tables, which this PR updates.
Possibly related PRs
flashinfer-ai/flashinfer#8686: This PR updates the same 17408→5120 forward cases that #8686 added, changing the selected epilogue while retaining the group size where applicable.
No actionable merge-blocking issue is established for these targeted GEMM rule updates. Merge after normal checks pass.
Pre-merge checks: 4 · 1
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Write docstrings for the functions missing them to satisfy the coverage threshold.
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Title check
The title names the change: planning the 17408→5120 and 16384→6144 forward rows with the row-half-release program at T-exact keys. The raw summary and PR description both describe this change in the r…
Description check
The description covers the purpose, the affected programs and rules, the rule-count change, and benchmark tables for the four GPUs. It also explains that outputs are bitwise identical on the changed r…
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Full details: Title check
Explanation
The title names the change: planning the 17408→5120 and 16384→6144 forward rows with the row-half-release program at T-exact keys. The raw summary and PR description both describe this change in the rule tables and the planner test. The title uses a conventional perf(...) prefix and is specific. It is long (137 characters), but it is still a single clear sentence about the main change.
Full details: Description check
Explanation
The description covers the purpose, the affected programs and rules, the rule-count change, and benchmark tables for the four GPUs. It also explains that outputs are bitwise identical on the changed rows. The template's checklist and Related Issues sections are not filled in. The Tests section is unchecked, and the experimental-tests fence still holds its placeholder comments. The description does not state whether the tests were run. The PR objectives mention that yyihuang requested a bot run of three test files, but the description does not record a test result. Because the PR touches flashinfer/experimental/ and the template requires an experimental-tests fence, the experimental track section is incomplete. The core description is complete, so the check passes, but the template items should be completed before merge.
Resolution
Complete the template sections before merge. Link the tracking issue or state that none exists under Related Issues. Check the Tests items and state the test results. Replace the placeholder experimental-tests fence with the test targets, for example tests/experimental/test_cake_dense_projection_det_gemm.py. If the PR is experimental, complete the Experimental Track checklist. The description also states that the new rules are not registered in flashinfer/aot.py. Confirm that claim against the build.json change, which adds AOT library entries for the new kernel.
Full details: Docstring Coverage
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Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 5 functions across 3 files. (2 skipped: 2 unsupported.)
Resolution
Write docstrings for the functions missing them to satisfy the coverage threshold.
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This PR changes the Cake
dense_projection_det_gemmpackage inflashinfer.experimental, the deterministic dense projection GEMM. Most programs in the package are BF16-operand GEMMs (forward, dgrad and wgrad), and one is an FP32 router GEMM. The package already ships one program that is built only forsm_107a. It is the half-tail tall program with a column-grouped raster, and its overlapped epilogue releases output by row half. This PR builds the same program from the same kernel source forsm_100aandsm_103a. No kernel source changes, and the number of compiled libraries in the package goes from 273 to 275. The PR plans this row-half-release program at 4 row rules. Each rule applies at a single token count T. Two of these rules already exist and cover the 17408→5120 forward (BF16 output) at T 16231 and 16384 onsm_100a. They used the overlapped half-tail program with the column-grouped raster in 12-column-tile groups. They now select the row-half-release program, still with 12-column-tile raster groups. The two new rules cover the 16384→6144 forward (the o_proj layer, BF16 output) at T 16231, one onsm_100aand one onsm_103a. They use 8-column-tile raster groups. Before this PR, that row used the overlapped half-tail program from the ragged rule. Onsm_103a, the 17408→5120 rows keep their current program. The rule count goes from 384 to 386 (sm_100a152 → 153,sm_103a107 → 108). Thesm_107arules are unchanged. The baseline is the previous Cake version of the package on main. On GB200, the 17408→5120 rows have a speedup of 1.013 at both T, and the o_proj row measures 1.018. On GB300 the o_proj row measures 1.013. On B200 the 17408→5120 rows measure 1.009 and 1.010, which is a small gain, and the o_proj row measures 1.018. On B300 the o_proj row measures 1.021. No changed row is slower on any of the four GPUs. Every rule keeps the K split of the row's previous plan (whole K per output tile), so outputs on those rows are bitwise identical to main on all four. All other rows of the 294-row shape list plan the same programs as main.Speedup of this PR over the previous Cake version on main. GB200 (
sm_100a, 152 SMs), GB300 (sm_103a, 152 SMs), B200 (sm_100a, 148 SMs), B300 (sm_103a, 148 SMs); CUDA 13.4, cold L2, BF16 output. Speedup = previous time / this PR time, and values above 1 mean this PR is faster.The package also ships FP32-output forms, weight-gradient (wgrad) programs and the FP32 router GEMM (run through BF16x3 emulation), on
sm_100a,sm_103aandsm_107a.Summary by CodeRabbit