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optimize radix cache. #968

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Merged
hiworldwzj merged 1 commit into from
Jul 11, 2025
+14 −7
Merged

optimize radix cache. #968

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21 changes: 14 additions & 7 deletions lightllm/server/router/dynamic_prompt/radix_cache.py
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Original file line number Diff line number Diff line change
Expand Up @@ -82,13 +82,20 @@ def is_leaf(self):
return len(self.children) == 0


def match(key, seq):
i = 0
for k, w in zip(key, seq):
if k != w:
break
i += 1
return i
def match(t1: torch.Tensor, t2: torch.Tensor) -> int:
# Ensure same shape for comparison: flatten and get min length
t1_flat = t1.flatten()
t2_flat = t2.flatten()
min_len = min(t1_flat.size(0), t2_flat.size(0))

# Compare elements and find first mismatch
diff = t1_flat[:min_len] != t2_flat[:min_len]
mismatch_indices = torch.nonzero(diff)

if mismatch_indices.numel() == 0:
return min_len # All matched up to min_len
else:
return mismatch_indices[0].item()
Comment on lines +85 to +98
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@gemini-code-assist gemini-code-assist bot Jul 11, 2025

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medium

Consider using torch.argmax instead of torch.nonzero for better efficiency. torch.nonzero creates a tensor of all indices where the condition is true, which can be memory-intensive. torch.argmax finds the index of the first True value without allocating memory for all mismatch indices.

Suggested change
def match(t1: torch.Tensor, t2: torch.Tensor) -> int:
# Ensure same shape for comparison: flatten and get min length
t1_flat = t1.flatten()
t2_flat = t2.flatten()
min_len = min(t1_flat.size(0), t2_flat.size(0))
# Compare elements and find first mismatch
diff = t1_flat[:min_len] != t2_flat[:min_len]
mismatch_indices = torch.nonzero(diff)
if mismatch_indices.numel() == 0:
return min_len # All matched up to min_len
else:
return mismatch_indices[0].item()
def match(t1: torch.Tensor, t2: torch.Tensor) -> int:
t1_flat = t1.flatten()
t2_flat = t2.flatten()
min_len = min(t1_flat.size(0), t2_flat.size(0))
if min_len == 0:
return 0
diff = t1_flat[:min_len] != t2_flat[:min_len]
if not torch.any(diff):
return min_len
return torch.argmax(diff.byte()).item()



class RadixCache:
Expand Down