TensorRT-LLMs/examples/llm-api/llm_runtime.py
Yan Chunwei 3e442922a3 [TRTLLM-9160][doc] add doc to llm_runtime.py (#9482)
Signed-off-by: Yan Chunwei <328693+Superjomn@users.noreply.github.com>
Signed-off-by: Mike Iovine <6158008+mikeiovine@users.noreply.github.com>
Signed-off-by: Mike Iovine <miovine@nvidia.com>
2025-12-05 17:50:12 -05:00

145 lines
4.4 KiB
Python

### :title Runtime Configuration Examples
### :order 6
### :section Customization
'''
This script demonstrates various runtime configuration options in TensorRT-LLM,
including KV cache management and CUDA graph optimizations.
**KV Cache Configuration:**
The KV cache (key-value cache) stores attention keys and values during inference,
which is crucial for efficient autoregressive generation. Proper KV cache configuration helps with:
1. **Memory Management**: Control GPU memory allocation for the key-value cache through
`free_gpu_memory_fraction`, balancing memory between model weights and cache storage.
2. **Block Reuse Optimization**: Enable `enable_block_reuse` to optimize memory usage
for shared prefixes across multiple requests, improving throughput for common prompts.
3. **Performance Tuning**: Configure cache block sizes and total capacity to match
your workload characteristics (batch size, sequence length, and request patterns).
Please refer to the `KvCacheConfig` API reference for more details.
**CUDA Graph Configuration:**
CUDA graphs help reduce kernel launch overhead and improve GPU utilization by capturing
and replaying GPU operations. Benefits include:
- Reduced kernel launch overhead for repeated operations
- Better GPU utilization through optimized execution
- Improved throughput for inference workloads
Please refer to the `CudaGraphConfig` API reference for more details.
**How to Run:**
Run all examples:
```bash
python llm_runtime.py
```
Run specific example:
```bash
python llm_runtime.py --example kv_cache
python llm_runtime.py --example cuda_graph
```
'''
import argparse
from tensorrt_llm import LLM, SamplingParams
from tensorrt_llm.llmapi import CudaGraphConfig, KvCacheConfig
def example_cuda_graph_config():
"""
Example demonstrating CUDA graph configuration for performance optimization.
CUDA graphs help with:
- Reduced kernel launch overhead
- Better GPU utilization
- Improved throughput for repeated operations
"""
print("\n=== CUDA Graph Configuration Example ===")
cuda_graph_config = CudaGraphConfig(
batch_sizes=[1, 2, 4],
enable_padding=True,
)
llm = LLM(
model="TinyLlama/TinyLlama-1.1B-Chat-v1.0",
cuda_graph_config=cuda_graph_config, # Enable CUDA graphs
max_batch_size=4,
max_seq_len=512,
kv_cache_config=KvCacheConfig(free_gpu_memory_fraction=0.5))
prompts = [
"Hello, my name is",
"The capital of France is",
"The future of AI is",
]
sampling_params = SamplingParams(max_tokens=50, temperature=0.8, top_p=0.95)
# This should benefit from CUDA graphs
outputs = llm.generate(prompts, sampling_params)
for output in outputs:
print(f"Prompt: {output.prompt}")
print(f"Generated: {output.outputs[0].text}")
print()
def example_kv_cache_config():
"""Example demonstrating KV cache configuration for memory management and performance."""
print("\n=== KV Cache Configuration Example ===")
print("\n1. KV Cache Configuration:")
llm_advanced = LLM(
model="TinyLlama/TinyLlama-1.1B-Chat-v1.0",
max_batch_size=8,
max_seq_len=1024,
kv_cache_config=KvCacheConfig(
# free_gpu_memory_fraction: the fraction of free GPU memory to allocate to the KV cache
free_gpu_memory_fraction=0.5,
# enable_block_reuse: whether to enable block reuse
enable_block_reuse=True))
prompts = [
"Hello, my name is",
"The capital of France is",
"The future of AI is",
]
outputs = llm_advanced.generate(prompts)
for i, output in enumerate(outputs):
print(f"Query {i+1}: {output.prompt}")
print(f"Answer: {output.outputs[0].text[:100]}...")
print()
def main():
"""
Main function to run all runtime configuration examples.
"""
parser = argparse.ArgumentParser(
description="Runtime Configuration Examples")
parser.add_argument("--example",
type=str,
choices=["kv_cache", "cuda_graph", "all"],
default="all",
help="Which example to run")
args = parser.parse_args()
if args.example == "kv_cache" or args.example == "all":
example_kv_cache_config()
if args.example == "cuda_graph" or args.example == "all":
example_cuda_graph_config()
if __name__ == "__main__":
main()