sgl-project--sglang/docs/platforms/apple_metal.md

Apple Silicon with Metal (MLX)

This document describes how run SGLang on Apple Silicon using Metal (MLX). If you encounter issues or have questions, please open an issue.

Install SGLang

You can install SGLang using one of the methods below.

Install from Source

# Use the default branch
git clone https://github.com/sgl-project/sglang.git
cd sglang

# Install sglang python package
pip install --upgrade pip
rm -f python/pyproject.toml && mv python/pyproject_other.toml python/pyproject.toml
uv pip install -e "python[all_mps]"

Launch of the Serving Engine

Launch the server with:

SGLANG_USE_MLX=1 python -m sglang.launch_server \
  --model <MODEL_ID_OR_PATH> \
  --disable-cuda-graph \
  --host 0.0.0.0

Key Parameters Explained:

1. SGLANG_USE_MLX=1 - Enables the use of MLX as the SGLang runtime backend (if disabled, SGLang will fall back to torch.mps, which has less support)
2. --disable-cuda-graph - Disables usage of CUDA graph, which is not relevant for Apple Metal.
3. --disable-overlap-schedule - Disables overlap scheduling (enabled/not present by default) achieved using MLX's async_eval()

Benchmarking with Requests

sglang.benchmark_one_batch calls the synchronous prefill/decode methods directly without going through the scheduler and the overlap code path.

sglang.benchmark_offline_throughput can toggle overlap scheduling as it uses the scheduler and the overlap code path by using the flag --disable-overlap-schedule.

Throughput Testing

Basic synchronous one batch throughput:

SGLANG_USE_MLX=1 python -m sglang.bench_one_batch \
  --model-path <MODEL_ID_OR_PATH> \
  --disable-cuda-graph \
  --tp-size 1 \
  --batch-size 1 \
  --input-len 60 \
  --output-len 10

Synchronous offline throughput:

SGLANG_USE_MLX=1 python -m sglang.bench_offline_throughput \
  --model-path <MODEL_ID_OR_PATH> \
  --disable-cuda-graph \
  --num-prompts 1 \
  --disable-overlap-schedule

Asynchronous offline throughput:

SGLANG_USE_MLX=1 python -m sglang.bench_offline_throughput \
  --model-path <MODEL_ID_OR_PATH> \
  --disable-cuda-graph \
  --num-prompts 1