[Bugfix] Allow vllm to still work if triton is not installed. (#6786)

Signed-off-by: Thomas Parnell <tpa@zurich.ibm.com>

requirements-cpu.txt

@@ -4,4 +4,3 @@
 # Dependencies for x86_64 CPUs
 torch == 2.4.0; platform_machine != "ppc64le"
 torchvision; platform_machine != "ppc64le"   # required for the image processor of phi3v, this must be updated alongside torch
-triton >= 2.2.0  # FIXME(woosuk): This is a hack to avoid import error.

requirements-openvino.txt

@@ -5,5 +5,3 @@
 torch >= 2.1.2
 openvino ~= 2024.3.0.dev
 optimum-intel[openvino] >= 1.18.1
-
-triton >= 2.2.0  # FIXME(woosuk): This is a hack to avoid import error.

requirements-tpu.txt

@@ -5,4 +5,3 @@
 # Currently, the TPU backend uses a nightly version of PyTorch XLA.
 # You can install the dependencies in Dockerfile.tpu.
 ray
-triton  # To avoid import errors

tests/kernels/test_sampler.py

@@ -5,11 +5,12 @@ import torch
 import triton
 import triton.language as tl
 
-from vllm.model_executor.layers.ops.sample import (
-    MAX_TRITON_N_COLS, _uniform_to_exponential, get_num_triton_sampler_splits,
-    sample)
+from vllm.model_executor.layers.ops.sample import (_uniform_to_exponential,
+                                                   sample)
 from vllm.model_executor.sampling_metadata import SamplingTensors
 from vllm.model_executor.utils import set_random_seed
+from vllm.triton_utils.sample import (MAX_TRITON_N_COLS,
+                                      get_num_triton_sampler_splits)
 
 SINGLE_SPLIT_VOCAB_SIZE = 32000  # llama/mistral/mixtral vocab size
 MULTI_SPLIT_VOCAB_SIZE = MAX_TRITON_N_COLS + 100

vllm/attention/ops/paged_attn.py

@@ -4,7 +4,10 @@ from typing import List, Optional, Tuple
 import torch
 
 from vllm import _custom_ops as ops
-from vllm.attention.ops.prefix_prefill import context_attention_fwd
+from vllm.triton_utils import HAS_TRITON
+
+if HAS_TRITON:
+    from vllm.attention.ops.prefix_prefill import context_attention_fwd
 
 # Should be the same as PARTITION_SIZE in `paged_attention_v2_launcher`.
 _PARTITION_SIZE = 512

vllm/model_executor/layers/fused_moe/__init__.py

@@ -1,14 +1,22 @@
-from vllm.model_executor.layers.fused_moe.fused_moe import (
-    fused_experts, fused_moe, fused_topk, get_config_file_name, grouped_topk)
 from vllm.model_executor.layers.fused_moe.layer import (FusedMoE,
                                                         FusedMoEMethodBase)
+from vllm.triton_utils import HAS_TRITON
 
 __all__ = [
-    "fused_moe",
-    "fused_topk",
-    "fused_experts",
-    "get_config_file_name",
-    "grouped_topk",
     "FusedMoE",
     "FusedMoEMethodBase",
 ]
+
+if HAS_TRITON:
+
+    from vllm.model_executor.layers.fused_moe.fused_moe import (
+        fused_experts, fused_moe, fused_topk, get_config_file_name,
+        grouped_topk)
+
+    __all__ += [
+        "fused_moe",
+        "fused_topk",
+        "fused_experts",
+        "get_config_file_name",
+        "grouped_topk",
+    ]

vllm/model_executor/layers/ops/sample.py

@@ -1,4 +1,3 @@
-import math
 from typing import Optional, Tuple
 
 import torch
@@ -6,21 +5,10 @@ import triton
 import triton.language as tl
 
 from vllm.model_executor.layers.ops.rand import seeded_uniform
+from vllm.triton_utils.sample import get_num_triton_sampler_splits
 
 _EPS = 1e-6
 
-# This is a hardcoded limit in Triton (max block size).
-MAX_TRITON_N_COLS = 131072
-
-
-def get_num_triton_sampler_splits(n_cols: int) -> int:
-    """Get the number of splits to use for Triton sampling.
-
-    Triton has a limit on the number of columns it can handle, so we need to
-    split the tensor and call the kernel multiple times if it's too large.
-    """
-    return math.ceil(n_cols / MAX_TRITON_N_COLS)
-
 
 def _multi_split_sample(
     probs: torch.Tensor,

vllm/model_executor/layers/quantization/fp8.py

@@ -6,8 +6,7 @@ from torch.nn.parameter import Parameter
 
 from vllm import _custom_ops as ops
 from vllm.logger import init_logger
-from vllm.model_executor.layers.fused_moe import (FusedMoE, FusedMoEMethodBase,
-                                                  fused_moe)
+from vllm.model_executor.layers.fused_moe import FusedMoE, FusedMoEMethodBase
 from vllm.model_executor.layers.linear import (LinearBase, LinearMethodBase,
                                                UnquantizedLinearMethod)
 from vllm.model_executor.layers.quantization.base_config import (
@@ -404,6 +403,7 @@ class Fp8MoEMethod(FusedMoEMethodBase):
               num_expert_group: Optional[int] = None,
               topk_group: Optional[int] = None) -> torch.Tensor:
 
+        from vllm.model_executor.layers.fused_moe import fused_moe
         return fused_moe(x,
                          layer.w13_weight,
                          layer.w2_weight,

vllm/model_executor/layers/sampler.py

@@ -6,7 +6,11 @@ from typing import Dict, List, Optional, Tuple
 import torch
 import torch.nn as nn
 
-from vllm.model_executor.layers.ops.sample import sample as sample_triton
+from vllm.triton_utils import HAS_TRITON
+
+if HAS_TRITON:
+    from vllm.model_executor.layers.ops.sample import sample as sample_triton
+
 from vllm.model_executor.sampling_metadata import (SamplingMetadata,
                                                    SamplingTensors,
                                                    SequenceGroupToSample)

vllm/model_executor/sampling_metadata.py

@@ -5,9 +5,9 @@ from typing import Dict, List, Optional, Tuple
 
 import torch
 
-from vllm.model_executor.layers.ops.sample import get_num_triton_sampler_splits
 from vllm.sampling_params import SamplingParams, SamplingType
 from vllm.sequence import SequenceData, SequenceGroupMetadata
+from vllm.triton_utils.sample import get_num_triton_sampler_splits
 from vllm.utils import (async_tensor_h2d, is_pin_memory_available,
                         make_tensor_with_pad, maybe_expand_dim)
 

vllm/triton_utils/__init__.py

@@ -1,6 +1,10 @@
-from vllm.triton_utils.custom_cache_manager import (
-    maybe_set_triton_cache_manager)
+from vllm.triton_utils.importing import HAS_TRITON
 
-__all__ = [
-    "maybe_set_triton_cache_manager",
-]
+__all__ = ["HAS_TRITON"]
+
+if HAS_TRITON:
+
+    from vllm.triton_utils.custom_cache_manager import (
+        maybe_set_triton_cache_manager)
+
+    __all__ += ["maybe_set_triton_cache_manager"]

vllm/triton_utils/importing.py

@@ -0,0 +1,11 @@
+from importlib.util import find_spec
+
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
+
+HAS_TRITON = find_spec("triton") is not None
+
+if not HAS_TRITON:
+    logger.info("Triton not installed; certain GPU-related functions"
+                " will be not be available.")

vllm/triton_utils/sample.py

@@ -0,0 +1,13 @@
+import math
+
+# This is a hardcoded limit in Triton (max block size).
+MAX_TRITON_N_COLS = 131072
+
+
+def get_num_triton_sampler_splits(n_cols: int) -> int:
+    """Get the number of splits to use for Triton sampling.
+
+    Triton has a limit on the number of columns it can handle, so we need to
+    split the tensor and call the kernel multiple times if it's too large.
+    """
+    return math.ceil(n_cols / MAX_TRITON_N_COLS)