vllm/examples/offline_inference/prefix_caching.py
Russell Bryant e489ad7a21
[Misc] Add SPDX-License-Identifier headers to python source files (#12628)
- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------

Signed-off-by: Russell Bryant <rbryant@redhat.com>
2025-02-02 11:58:18 -08:00

86 lines
3.0 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from vllm import LLM, SamplingParams
from vllm.distributed import cleanup_dist_env_and_memory
# NOTE: This is just a running example. For benchmarking purpose,
# please see benchmarks/benchmark_prefix_caching.py
# Common prefix.
prefix = (
"You are an expert school principal, skilled in effectively managing "
"faculty and staff. Draft 10-15 questions for a potential first grade "
"Head Teacher for my K-12, all-girls', independent school that emphasizes "
"community, joyful discovery, and life-long learning. The candidate is "
"coming in for a first-round panel interview for a 8th grade Math "
"teaching role. They have 5 years of previous teaching experience "
"as an assistant teacher at a co-ed, public school with experience "
"in middle school math teaching. Based on these information, fulfill "
"the following paragraph: ")
# Sample prompts.
prompts = [
"Hello, my name is",
"The president of the United States is",
"The capital of France is",
"The future of AI is",
]
generating_prompts = [prefix + prompt for prompt in prompts]
# Create a sampling params object.
sampling_params = SamplingParams(temperature=0.0)
# Create an LLM without prefix caching as a baseline.
regular_llm = LLM(model="facebook/opt-125m", gpu_memory_utilization=0.4)
print("Results without `enable_prefix_caching`")
# Generate texts from the prompts. The output is a list of RequestOutput objects
# that contain the prompt, generated text, and other information.
outputs = regular_llm.generate(generating_prompts, sampling_params)
regular_generated_texts = []
# Print the outputs.
for output in outputs:
prompt = output.prompt
generated_text = output.outputs[0].text
regular_generated_texts.append(generated_text)
print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
print("-" * 80)
# Destroy the LLM object and free up the GPU memory.
del regular_llm
cleanup_dist_env_and_memory()
# Create an LLM with prefix caching enabled.
prefix_cached_llm = LLM(model="facebook/opt-125m",
enable_prefix_caching=True,
gpu_memory_utilization=0.4)
# Warmup so that the shared prompt's KV cache is computed.
prefix_cached_llm.generate(generating_prompts[0], sampling_params)
# Generate with prefix caching.
outputs = prefix_cached_llm.generate(generating_prompts, sampling_params)
print("Results with `enable_prefix_caching`")
cached_generated_texts = []
# Print the outputs. You should see the same outputs as before.
for output in outputs:
prompt = output.prompt
generated_text = output.outputs[0].text
cached_generated_texts.append(generated_text)
print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
print("-" * 80)
# Compare the results and display the speedup
generated_same = all([
regular_generated_texts[i] == cached_generated_texts[i]
for i in range(len(prompts))
])
print(f"Generated answers are the same: {generated_same}")