parallel.md

Parallel Inference

Merge the JSON fragments below into a complete model config.

Launch with torchrun and a process count matching the parallel configuration. With only sequence and CFG parallelism, N = seq_p_size × cfg_p_size (unset values count as 1); for example, four-way sequence parallelism with two-way CFG parallelism needs 8 processes.

CFG parallelism requires enable_cfg=true and cannot be used with CFG-disabled distilled configs.

LightX2V supports distributed parallel inference, enabling the utilization of multiple GPUs for inference. The DiT component supports two parallel attention mechanisms: Ulysses and Ring, while also supporting Cfg parallel inference. Parallel inference significantly reduces inference time and alleviates memory overhead on each GPU.

DiT Parallel Configuration

1. Ulysses Parallel

Configuration method:

{
    "parallel": {
        "seq_p_size": 4,
        "seq_p_attn_type": "ulysses"
    }
}

2. Ring Parallel

Configuration method:

{
    "parallel": {
        "seq_p_size": 4,
        "seq_p_attn_type": "ring"
    }
}

Cfg Parallel Configuration

Configuration method:

{
    "enable_cfg": true,
    "parallel": {
        "cfg_p_size": 2
    }
}

Hybrid Parallel Configuration

Configuration method:

{
    "enable_cfg": true,
    "parallel": {
        "seq_p_size": 4,
        "seq_p_attn_type": "ulysses",
        "cfg_p_size": 2
    }
}

Usage

Parallel inference configuration files are available here

By specifying --config_json to a specific config file, you can test parallel inference.

Here are some run scripts for your use.