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Refactor JIT compilation (+NVRTC support)#94

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May 7, 2025
Merged

Refactor JIT compilation (+NVRTC support)#94
LyricZhao merged 25 commits into
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nvrtc

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@lucifer1004

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With this PR, the JIT compilation time is reduced by ~60% when using NVCC, ~80% when using NVRTC w/o PCH, and ~90% when using NVRTC w/ PCH.

Benchmark on Xeon(R) Platinum 8480C + H100 HBM:

m n k compilation time (s) TFLOPS
baseline NVCC NVRTC NVRTC+PCH baseline NVCC NVRTC NVRTC+PCH
64 2112 7168 5.95 2.12 0.96 0.35 154 154 153 153
64 24576 1536 6.43 2.55 1.37 0.78 230 230 231 230
64 32768 512 6.06 2.20 0.99 0.40 180 180 180 180
64 7168 16384 6.11 2.25 1.01 0.43 289 290 289 289
64 4096 7168 5.98 2.15 0.97 0.37 207 207 206 206
64 7168 2048 6.03 2.19 1.01 0.42 188 189 187 188
128 2112 7168 5.98 2.18 0.96 0.37 283 280 281 282
128 24576 1536 6.38 2.56 1.39 0.78 440 435 434 434
128 32768 512 6.00 2.18 0.99 0.40 334 336 330 332
128 7168 16384 6.24 2.40 1.18 0.59 534 534 534 533
128 4096 7168 6.04 2.21 1.03 0.43 370 371 370 371
128 7168 2048 6.19 2.38 1.19 0.62 332 334 331 332
4096 2112 7168 6.09 2.30 1.08 0.49 1053 1058 1113 1114
4096 24576 1536 6.14 2.33 1.10 0.50 1288 1286 1290 1289
4096 32768 512 6.23 2.41 1.21 0.61 913 912 912 911
4096 7168 16384 6.31 2.51 1.27 0.68 1524 1524 1459 1458
4096 4096 7168 6.28 2.47 1.27 0.68 1446 1445 1394 1396
4096 7168 2048 6.18 2.40 1.21 0.61 1240 1243 1234 1237

Note that there is some perf drop when using NVRTC due to a known bug of NVRTC which leads to extra instructions (but in the m=4096,n=2112,k=7168 case, NVRTC version was faster, which was a bit strange). So NVCC is kept as the default compiler for now, while NVRTC can be enabled with extra env var DG_JIT_USE_NVRTC.

Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Gabriel Wu <13583761+lucifer1004@users.noreply.github.com>
feat: add compat for older drivers and Windows
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
Signed-off-by: Zihua Wu <13583761+lucifer1004@users.noreply.github.com>
@LyricZhao LyricZhao requested review from LyricZhao and zheanxu May 7, 2025 03:18
@LyricZhao LyricZhao merged commit bfe983c into main May 7, 2025
@LyricZhao LyricZhao deleted the nvrtc branch May 7, 2025 03:42
@thefacetakt

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Hi

I was wondering, is there a reason for removing DG_BENCH_POWER_LIMITED and other bench_kineto-related options?

LyricZhao added a commit that referenced this pull request Apr 16, 2026
* Deal corner cases

* fix bf16 as well

* fix k grouped as well

* simplify

* Some refactors

* Minor fix

* Minor fix

---------

Co-authored-by: Chenggang Zhao <chenggangz@deepseek.com>
asanpardazzagros3-droid added a commit to asanpardazzagros3-droid/DeepGEMM that referenced this pull request Jul 3, 2026
DeepGEMM is a unified, high-performance tensor core kernel library that brings together the key computation primitives of modern large language models — GEMMs (FP8, FP4, BF16), fused MoE with overlapped communication (Mega MoE), MQA scoring for the lightning indexer, HyperConnection (HC), and more — into a single, cohesive CUDA codebase. All kernels are compiled at runtime via a lightweight Just-In-Time (JIT) module, requiring no CUDA compilation during installation.

DeepGEMM leverages some concepts from CUTLASS and CuTe, but avoids heavy reliance on their templates or algebras. The library is designed for simplicity, with only a limited number of core kernel functions, making it a clean and accessible resource for learning NVIDIA GPU kernel optimization techniques.

Despite its lightweight design, DeepGEMM's performance matches or exceeds expert-tuned libraries across various matrix shapes.

News
2026.04.16: Mega MoE, FP8xFP4 GEMM, FP4 Indexer, PDL, faster JIT compilation and more.
Please see deepseek-ai#304 for more details.
For Mega MoE benchmarks, refer to deepseek-ai#316.
2025.09.28: DeepGEMM now supports scoring kernels (weighted ReLU MQA logits) for the lightning indexer for DeepSeek v3.2.
Please see deepseek-ai#200 for more details.
2025.07.20: DeepGEMM now supports both SM90/SM100, and has a full refactor with a low-CPU-overhead JIT CPP module.
NVRTC and post-compilation SASS optimization are all disabled.
NVRTC will be supported later.
As NVCC 12.9 will automatically do the FFMA interleaving, all post optimizations will be no longer supported.
Please see deepseek-ai#112 for more details.
2025.05.14: DeepGEMM now offers weight gradient kernels for dense and MoE backward! See deepseek-ai#95 for details.
2025.05.07: DeepGEMM now supports NVRTC with up to 10x compilation speedup! See deepseek-ai#94 for details. Please use DG_JIT_USE_NVRTC=1 to enable it (may have performance loss with some cases).
2025.04.18: DeepGEMM now achieves up to 1550 TFLOPS on H800! See deepseek-ai#74, deepseek-ai#78, deepseek-ai#81, deepseek-ai#86 and 340d988 for details.
Quick start
Requirements
NVIDIA SM90 or SM100 architecture GPU
Python 3.8 or higher
Compilers with C++20 support
CUDA Toolkit:
CUDA 12.3 or higher for SM90
We highly recommend 12.9 or higher for the best performance
CUDA 12.9 or higher for SM100
PyTorch 2.1 or higher
CUTLASS 4.0 or higher (could be cloned by Git submodule)
{fmt} library (could be cloned by Git submodule)
Development
# Submodule must be cloned
git clone --recursive git@github.com:deepseek-ai/DeepGEMM.git
cd DeepGEMM

# Link some essential includes and build the CPP JIT module
cat develop.sh
./develop.sh
Installation
cat install.sh
./install.sh
Then, import deep_gemm in your Python project, and enjoy!

Interfaces
Notices
This library provides optimized GEMM kernels for NVIDIA GPUs with a naming convention: D = C + A @ B. The input shape layout is NT (non-transposed A, transposed B). While the SM90 implementation supports only the NT memory layout (row-major, col-major), the SM100 implementation supports all memory layouts (NT, TN, NN, TT). For example, fp8_gemm_nt will do a D = C + A @ B.T

For both architectures, the LHS scaling factor is required to have a TMA-aligned and transposed layout. And the data format for the scaling factor of SM90 and SM100 is different:

SM90 requires scaling factors in FP32 format.
SM100 requires scaling factors in packed UE8M0 format, which packs 4 UE8M0 into a single torch.int.
Please note that operations like input transposition or FP8 casting must be handled separately by the user, please implement or fuse them into prior kernels independently. While the library provides some simple PyTorch utility functions, these may result in slower performance, but our primary focus is on optimizing the GEMM kernels themselves.

Normal dense GEMMs (non-grouped)
To perform a basic non-grouped FP8 GEMM, call the fp8_gemm_{nt, nn, tn, tt} function. For more details, please refer to the function documentation.

Grouped GEMMs (contiguous layout)
Unlike traditional grouped GEMMs in CUTLASS, DeepGEMM groups only the M-axis, while N and K must remain fixed. This design is tailored for scenarios where experts in an MoE model share the same shape. For training forward passes or inference prefilling, where each expert may process a varying number of tokens, we concatenate these tokens into a single tensor, referred to as the "contiguous" layout. Note that each expert segment must be aligned to the GEMM M block size (get_mk_alignment_for_contiguous_layout()). For more information, please refer to the m_grouped_fp8_gemm_{nt, nn}_contiguous function documentation.

We also provide a K-axis-grouped API for MoE weight backward (with M and N must remain fixed), please refer to k_grouped_fp8_gemm_tn_contiguous for more information.

Grouped GEMMs (masked layout)
During the inference decoding phase, when CUDA graph is enabled and the CPU is unaware of the number of tokens each expert receives, we support masked grouped GEMMs. By providing a mask tensor, the kernel computes only the valid portions.

Use m_grouped_fp8_gemm_nt_masked for this purpose and consult the relevant documentation. An example usage is to use the output of low-latency kernels from DeepEP as input.

V3.2 MQA kernels for the indexer
The kernel family has two versions, non-paged (for prefilling) and paged (for decoding). Take the non-paged version fp8_mqa_logits as an example. It has 6 inputs:

q, E4M3 tensor with shape [seq_len, num_heads, head_dim]
kv, E4M3 tensor (shaped as [seq_len_kv, head_dim]) with float SF (shaped as [seq_len_kv])
weights, float tensor with shape [seq_len, num_heads]
cu_seq_len_k_start and cu_seq_len_k_end, int tensor with shape [seq_len]
clean_logits, whether to clean the unfilled logits into -inf
The output tensor is shaped as [seq_len, seq_len_kv], indicating token-to-token logits. For each token i in q, it will iterate all tokens j from [cu_seq_len_k_start[i], cu_seq_len_k_end[i]), and calculate the logit out[i, j] as:

kv_j = kv[0][j, :] * kv[1][j].unsqueeze(1)  # [head_dim]
out_ij = q[i, :, :] @ kv_j  # [num_heads]
out_ij = out_ij.relu() * weights[i, :]  # [num_heads]
out_ij = out_ij.sum()  # Scalar
For more details and the paged version fp8_paged_mqa_logits, please refer to tests/test_attention.py.

Mega MoE
Mega MoE fuses and overlaps EP dispatch, linear 1 (FP8xFP4), SwiGLU, linear 2 (FP8xFP4), and EP combine into a single mega-kernel, overlapping NVLink communication and tensor core computation. It requires multi-process launch with symmetric memory. Usage:

# Allocate symmetric memory buffer
# NOTES: requires PyTorch >= 2.9
buffer = deep_gemm.get_symm_buffer_for_mega_moe(
    group, num_experts, num_max_tokens_per_rank, num_topk, hidden, intermediate_hidden
)

# Transform weights (FP4 with UE8M0 SF) into the required layout
transformed_l1, transformed_l2 = deep_gemm.transform_weights_for_mega_moe(l1_weights, l2_weights)

# Copy inputs into the buffer before each call
# You may fuse these into previous kernels
buffer.x[:num_tokens].copy_(x_fp8)
buffer.x_sf[:num_tokens].copy_(x_sf)
buffer.topk_idx[:num_tokens].copy_(topk_idx)
buffer.topk_weights[:num_tokens].copy_(topk_weights)

# Run the fused mega MoE kernel
y = torch.empty((num_tokens, hidden), dtype=torch.bfloat16, device='cuda')
deep_gemm.fp8_fp4_mega_moe(y, transformed_l1, transformed_l2, buffer)
For the full example with multi-process setup and benchmarking, please refer to tests/test_mega_moe.py.

Utilities
The library provides some utility functions besides the above kernels:

deep_gemm.set_num_sms / get_num_sms: set/get the maximum SM count to use
deep_gemm.set_tc_util / get_tc_util: set/get an approximated tensor core utilization ratio
deep_gemm.set_pdl / get_pdl: enable/disable Programmatic Dependent Launch (PDL)
deep_gemm.set_mk_alignment_for_contiguous_layout / get_mk_alignment_for_contiguous_layout: set/get the group-level M/K alignment for contiguous layout
deep_gemm.get_theoretical_mk_alignment_for_contiguous_layout: get the theoretical minimum M/K alignment
deep_gemm.set_ignore_compile_dims: configure dimensions to ignore during JIT compilation
deep_gemm.set_block_size_multiple_of: constrain block sizes to be multiples of a given value
deep_gemm.transform_sf_into_required_layout: transform scaling factors into the required layout
deep_gemm.get_tma_aligned_size: get the required TMA alignment size
deep_gemm.get_mn_major_tma_aligned_tensor: get a MN-major TMA-aligned tensor
deep_gemm.get_mn_major_tma_aligned_packed_ue8m0_tensor: get a MN-major TMA-aligned tensor (with packing FP32 into UE8M0)
deep_gemm.get_k_grouped_mn_major_tma_aligned_packed_ue8m0_tensor: K-grouped GEMM packing kernel
The library also provides some environment variables, which may be useful:

General
DG_JIT_DEBUG: 0 or 1, print JIT debugging information, 0 by default
DG_PRINT_CONFIGS: 0 or 1, print selected configs for each shape, 0 by default
JIT cache
DG_JIT_CACHE_DIR: string, cache directory for compiled kernels, $HOME/.deep_gemm by default
Compiler selection
DG_JIT_USE_NVRTC: 0 or 1, use NVRTC instead of NVCC (faster compilation, may have lower performance for some cases), 0 by default
DG_JIT_NVCC_COMPILER: string, NVCC compiler path; defaults to torch.utils.cpp_extension.CUDA_HOME
DG_JIT_CPP_STANDARD: integer, C++ standard version, 20 by default
Compiler output
DG_JIT_PRINT_COMPILER_COMMAND: 0 or 1, print compilation commands, 0 by default
DG_JIT_PTXAS_VERBOSE: 0 or 1, show detailed PTXAS output, 0 by default
DG_JIT_PTXAS_CHECK: 0 or 1, assert no local memory usage in compiled kernels, 0 by default
DG_JIT_PRINT_LOAD_TIME: 0 or 1, print kernel load time, 0 by default
Debug and profiling
DG_JIT_WITH_LINEINFO: 0 or 1, embed source line info for profiling tools, 0 by default
DG_JIT_DUMP_ASM: 0 or 1, dump both PTX and SASS, 0 by default
DG_JIT_DUMP_PTX: 0 or 1, dump PTX output, 0 by default
DG_JIT_DUMP_SASS: 0 or 1, dump SASS output, 0 by default
DG_COMM_KERNEL_DEBUG: 0 or 1, zero symmetric buffer before each Mega MoE call for debugging, 0 by default
DG_USE_NVIDIA_TOOLS: 0 or 1, skip internal profiling when running under external NVIDIA tools, 0 by default
Build options
DG_SKIP_CUDA_BUILD: 0 or 1, skip CUDA extension build during installation, 0 by default
DG_FORCE_BUILD: 0 or 1, force local build instead of downloading pre-built wheels, 0 by default
DG_JIT_USE_RUNTIME_API: 0 or 1, use CUDA Runtime API for kernel loading (requires CUDA runtime >= 12.8), 0 by default
For additional examples and details, please refer to the test code or review the corresponding Python documentation.

Acknowledgement
DeepGEMM is inspired by the CUTLASS project. Thanks and respect to the developers!

License
This code repository is released under the MIT License.

Citation
@misc{deepgemm2025,
      title={DeepGEMM: clean and efficient BLAS kernel library on GPU}, 
      author={Chenggang Zhao and Zhean Xu and Liang Zhao and Jiashi Li and Chenhao Xu and Anyi Xu and Shengyu Liu and Kexing Zhou and Kuai Yu},
      year={2025},
      publisher = {GitHub},
      howpublished = {\url{https://github.com/deepseek-ai/DeepGEMM}},
}
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