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[MISC] Add prefix cache reset to LMCache CPU offload example #27248

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[MISC] Add prefix cache reset to LMCache CPU offload example #27248

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[MISC] Add prefix cache reset to LMCache CPU offload example
sakunkun Oct 21, 2025
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Merge branch 'main' into main
sakunkun Oct 23, 2025
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3 changes: 3 additions & 0 deletions examples/others/lmcache/cpu_offload_lmcache.py
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Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,9 @@ def main():
print_output(llm, first_prompt, sampling_params, "first")

time.sleep(1)
# Clear vLLM's internal prefix cache to force the second request
# to fetch cached KVs from LMCache
llm.reset_prefix_cache()
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@gemini-code-assist gemini-code-assist bot Oct 21, 2025

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high

The reset_prefix_cache method can fail if there are still blocks in use, and it returns a boolean indicating success or failure. The example should check this return value and raise an error if it's False. This will make the example more robust and prevent confusion if the cache reset fails, which would cause the example to not demonstrate the intended LMCache loading behavior.

Suggested change
llm.reset_prefix_cache()
if not llm.reset_prefix_cache():
raise RuntimeError(
"Failed to reset prefix cache. The example may not run as expected."
)


# print the second output
print_output(llm, second_prompt, sampling_params, "second")
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