README.md

Benchmark for C++ Runtime

This document explains how to benchmark the models supported by TensorRT-LLM on a single GPU, a single node with multiple GPUs or multiple nodes with multiple GPUs.

Usage

1. Build TensorRT-LLM and benchmarking source code

Please follow the installation document to build TensorRT-LLM.

Note that the benchmarking source code for C++ runtime is not built by default, you can use the argument --benchmarks in build_wheel.py to build that.

Windows users: Follow the Windows installation document instead, and be sure to set DLL paths as specified in Extra Steps for C++ Runtime Usage.

2. Launch C++ benchmarking (Fixed BatchSize/InputLen/OutputLen)

Prepare TensorRT-LLM engine(s)

Before you launch C++ benchmarking, please make sure that you have already built engine(s) using TensorRT-LLM API, C++ benchmarking code cannot generate engine(s) for you.

You can use the build.py script to build the engine(s). Alternatively, if you have already benchmarked Python Runtime, you can reuse the engine(s) built by benchmarking code, please see that document.

Launch benchmarking

For detailed usage, you can do the following

cd cpp/build

# You can directly execute the binary for help information
./benchmarks/gptSessionBenchmark --help
./benchmarks/bertBenchmark --help

Take GPT-350M as an example for single GPU

./benchmarks/gptSessionBenchmark \
    --model gpt_350m \
    --engine_dir "../../benchmarks/gpt_350m/" \
    --batch_size "1" \
    --input_output_len "60,20"

# Expected output:
# [BENCHMARK] batch_size 1 input_length 60 output_length 20 latency(ms) 40.81

Take GPT-175B as an example for multiple GPUs

mpirun -n 8 ./benchmarks/gptSessionBenchmark \
    --model gpt_175b \
    --engine_dir "../../benchmarks/gpt_175b/" \
    --batch_size "1" \
    --input_output_len "60,20"

# Expected output:
# [BENCHMARK] batch_size 1 input_length 60 output_length 20 latency(ms) 792.14

If you want to obtain context and generation logits, you could build an enigne with --gather_all_token_logits and run gptSessionBenchmark with --print_all_logits. This will print a large number of logit values and has a certain impact on performance.

Please note that the expected outputs in that document are only for reference, specific performance numbers depend on the GPU you're using.

3. Launch Batch Manager benchmarking (Inflight/V1 batching)

Prepare dataset

Run a preprocessing script to prepare dataset. This script converts the prompts(string) in the dataset to input_ids.

python3 prepare_dataset.py \
    --dataset <path/to/dataset> \
    --max_input_len 300 \
    --tokenizer_dir <path/to/tokenizer> \
    --tokenizer_type auto \
    --output preprocessed_dataset.json

For tokenizer_dir, specifying the path to the local tokenizer that have already been downloaded, or simply the name of the tokenizer from HuggingFace like gpt2 will both work. The tokenizer will be downloaded automatically for the latter case.

Prepare TensorRT-LLM engines

Please make sure that the engines are built with argument --use_inflight_batching and --remove_input_padding if you'd like to benchmark inflight batching, for more details, please see the document in TensorRT-LLM examples.

Launch benchmarking

For detailed usage, you can do the following

cd cpp/build

# You can directly execute the binary for help information
./benchmarks/gptManagerBenchmark --help

Take GPT-350M as an example for single GPU V1 batching

./benchmarks/gptManagerBenchmark \
    --model gpt \
    --engine_dir ../../examples/gpt/trt_engine/gpt2/fp16/1-gpu/ \
    --type V1 \
    --dataset ../../benchmarks/cpp/preprocessed_dataset.json

Take GPT-350M as an example for 2-GPU inflight batching

mpirun -n 2 ./benchmarks/gptManagerBenchmark \
    --model gpt \
    --engine_dir ../../examples/gpt/trt_engine/gpt2-ib/fp16/2-gpu/ \
    --type IFB \
    --dataset ../../benchmarks/cpp/preprocessed_dataset.json