Use torch.compile for scaling penalty (#3133)

python/sglang/srt/sampling/penaltylib/penalizers/repetition_penalty.py

@@ -3,11 +3,16 @@ from typing import List
 import torch
 
 from sglang.srt.sampling.penaltylib.orchestrator import _BatchedPenalizer, _TokenIDs
-from sglang.srt.utils import is_cuda_available
+from sglang.srt.utils import get_compiler_backend
 
-is_cuda = is_cuda_available()
-if is_cuda:
-    from sgl_kernel import sampling_scaling_penalties
+
+@torch.compile(dynamic=True, backend=get_compiler_backend())
+def apply_scaling_penalties(logits, scaling_penalties):
+    logits[:] = torch.where(
+        logits > 0,
+        logits / scaling_penalties,
+        logits * scaling_penalties,
+    )
 
 
 class BatchedRepetitionPenalizer(_BatchedPenalizer):
@@ -61,16 +66,7 @@ class BatchedRepetitionPenalizer(_BatchedPenalizer):
         self.cumulated_repetition_penalties[mask] = self.repetition_penalties[mask]
 
     def _apply(self, logits: torch.Tensor) -> torch.Tensor:
-        if is_cuda:
-            return sampling_scaling_penalties(
-                logits, self.cumulated_repetition_penalties
-            )
-        else:
-            return torch.where(
-                logits > 0,
-                logits / self.cumulated_repetition_penalties,
-                logits * self.cumulated_repetition_penalties,
-            )
+        apply_scaling_penalties(logits, self.cumulated_repetition_penalties)
 
     def _filter(self, indices_to_keep: List[int], indices_tensor_to_keep: torch.Tensor):
         self.repetition_penalties = self.repetition_penalties[indices_tensor_to_keep]

python/sglang/srt/sampling/sampling_batch_info.py

@@ -7,14 +7,11 @@ from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple
 
 import torch
 
-from sglang.srt.utils import is_cuda_available
-
-is_cuda = is_cuda_available()
-if is_cuda:
-    from sgl_kernel import sampling_scaling_penalties
-
 import sglang.srt.sampling.penaltylib as penaltylib
 from sglang.srt.sampling.custom_logit_processor import CustomLogitProcessor
+from sglang.srt.sampling.penaltylib.penalizers.repetition_penalty import (
+    apply_scaling_penalties,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -386,14 +383,7 @@ class SamplingBatchInfo:
 
         # repetition
         if self.scaling_penalties is not None:
-            if is_cuda:
-                logits[:] = sampling_scaling_penalties(logits, self.scaling_penalties)
-            else:
-                logits[:] = torch.where(
-                    logits > 0,
-                    logits / self.scaling_penalties,
-                    logits * self.scaling_penalties,
-                )
+            apply_scaling_penalties(logits, self.scaling_penalties)
 
         # Apply regex vocab_mask
         if self.vocab_mask is not None: