docs/source/en/optimization/tgate.md

# T-GATE

[T-GATE](https://github.com/HaozheLiu-ST/T-GATE/tree/main) accelerates inference for [Stable Diffusion](../api/pipelines/stable_diffusion/overview), [PixArt](../api/pipelines/pixart), and [Latency Consistency Model](../api/pipelines/latent_consistency_models.md) pipelines by skipping the cross-attention calculation once it converges. This method doesn't require any additional training and it can speed up inference from 10-50%. T-GATE is also compatible with other optimization methods like [DeepCache](./deepcache).

Before you begin, make sure you install T-GATE.

```bash
pip install tgate
pip install -U torch diffusers transformers accelerate DeepCache
```


To use T-GATE with a pipeline, you need to use its corresponding loader.

| Pipeline | T-GATE Loader |
|---|---|
| PixArt | TgatePixArtLoader |
| Stable Diffusion XL | TgateSDXLLoader |
| Stable Diffusion XL + DeepCache | TgateSDXLDeepCacheLoader |
| Stable Diffusion | TgateSDLoader |
| Stable Diffusion + DeepCache | TgateSDDeepCacheLoader |

Next, create a `TgateLoader` with a pipeline, the gate step (the time step to stop calculating the cross attention), and the number of inference steps. Then call the `tgate` method on the pipeline with a prompt, gate step, and the number of inference steps.

Let's see how to enable this for several different pipelines.

<hfoptions id="pipelines">
<hfoption id="PixArt">

Accelerate `PixArtAlphaPipeline` with T-GATE:

```py
import torch
from diffusers import PixArtAlphaPipeline
from tgate import TgatePixArtLoader

pipe = PixArtAlphaPipeline.from_pretrained("PixArt-alpha/PixArt-XL-2-1024-MS", torch_dtype=torch.float16)

gate_step = 8
inference_step = 25
pipe = TgatePixArtLoader(
       pipe,
       gate_step=gate_step,
       num_inference_steps=inference_step,
).to("cuda")

image = pipe.tgate(
       "An alpaca made of colorful building blocks, cyberpunk.",
       gate_step=gate_step,
       num_inference_steps=inference_step,
).images[0]
```
</hfoption>
<hfoption id="Stable Diffusion XL">

Accelerate `StableDiffusionXLPipeline` with T-GATE:

```py
import torch
from diffusers import StableDiffusionXLPipeline
from diffusers import DPMSolverMultistepScheduler
from tgate import TgateSDXLLoader

pipe = StableDiffusionXLPipeline.from_pretrained(
            "stabilityai/stable-diffusion-xl-base-1.0",
            torch_dtype=torch.float16,
            variant="fp16",
            use_safetensors=True,
)
pipe.scheduler = DPMSolverMultistepScheduler.from_config(pipe.scheduler.config)

gate_step = 10
inference_step = 25
pipe = TgateSDXLLoader(
       pipe,
       gate_step=gate_step,
       num_inference_steps=inference_step,
).to("cuda")

image = pipe.tgate(
       "Astronaut in a jungle, cold color palette, muted colors, detailed, 8k.",
       gate_step=gate_step,
       num_inference_steps=inference_step
).images[0]
```
</hfoption>
<hfoption id="StableDiffusionXL with DeepCache">

Accelerate `StableDiffusionXLPipeline` with [DeepCache](https://github.com/horseee/DeepCache) and T-GATE:

```py
import torch
from diffusers import StableDiffusionXLPipeline
from diffusers import DPMSolverMultistepScheduler
from tgate import TgateSDXLDeepCacheLoader

pipe = StableDiffusionXLPipeline.from_pretrained(
            "stabilityai/stable-diffusion-xl-base-1.0",
            torch_dtype=torch.float16,
            variant="fp16",
            use_safetensors=True,
)
pipe.scheduler = DPMSolverMultistepScheduler.from_config(pipe.scheduler.config)

gate_step = 10
inference_step = 25
pipe = TgateSDXLDeepCacheLoader(
       pipe,
       cache_interval=3,
       cache_branch_id=0,
).to("cuda")

image = pipe.tgate(
       "Astronaut in a jungle, cold color palette, muted colors, detailed, 8k.",
       gate_step=gate_step,
       num_inference_steps=inference_step
).images[0]
```
</hfoption>
<hfoption id="Latent Consistency Model">

Accelerate `latent-consistency/lcm-sdxl` with T-GATE:

```py
import torch
from diffusers import StableDiffusionXLPipeline
from diffusers import UNet2DConditionModel, LCMScheduler
from diffusers import DPMSolverMultistepScheduler
from tgate import TgateSDXLLoader

unet = UNet2DConditionModel.from_pretrained(
    "latent-consistency/lcm-sdxl",
    torch_dtype=torch.float16,
    variant="fp16",
)
pipe = StableDiffusionXLPipeline.from_pretrained(
    "stabilityai/stable-diffusion-xl-base-1.0",
    unet=unet,
    torch_dtype=torch.float16,
    variant="fp16",
)
pipe.scheduler = LCMScheduler.from_config(pipe.scheduler.config)

gate_step = 1
inference_step = 4
pipe = TgateSDXLLoader(
       pipe,
       gate_step=gate_step,
       num_inference_steps=inference_step,
       lcm=True
).to("cuda")

image = pipe.tgate(
       "Astronaut in a jungle, cold color palette, muted colors, detailed, 8k.",
       gate_step=gate_step,
       num_inference_steps=inference_step
).images[0]
```
</hfoption>
</hfoptions>

T-GATE also supports [`StableDiffusionPipeline`] and [PixArt-alpha/PixArt-LCM-XL-2-1024-MS](https://hf.co/PixArt-alpha/PixArt-LCM-XL-2-1024-MS).

## Benchmarks
| Model                 | MACs     | Param     | Latency | Zero-shot 10K-FID on MS-COCO |
|-----------------------|----------|-----------|---------|---------------------------|
| SD-1.5                | 16.938T  | 859.520M  | 7.032s  | 23.927                    |
| SD-1.5 w/ T-GATE       | 9.875T   | 815.557M  | 4.313s  | 20.789                    |
| SD-2.1                | 38.041T  | 865.785M  | 16.121s | 22.609                    |
| SD-2.1 w/ T-GATE       | 22.208T  | 815.433 M | 9.878s  | 19.940                    |
| SD-XL                 | 149.438T | 2.570B    | 53.187s | 24.628                    |
| SD-XL w/ T-GATE        | 84.438T  | 2.024B    | 27.932s | 22.738                    |
| Pixart-Alpha          | 107.031T | 611.350M  | 61.502s | 38.669                    |
| Pixart-Alpha w/ T-GATE | 65.318T  | 462.585M  | 37.867s | 35.825                    |
| DeepCache (SD-XL)     | 57.888T  | -         | 19.931s | 23.755                    |
| DeepCache w/ T-GATE    | 43.868T  | -         | 14.666s | 23.999                    |
| LCM (SD-XL)           | 11.955T  | 2.570B    | 3.805s  | 25.044                    |
| LCM w/ T-GATE          | 11.171T  | 2.024B    | 3.533s  | 25.028                    |
| LCM (Pixart-Alpha)    | 8.563T   | 611.350M  | 4.733s  | 36.086                    |
| LCM w/ T-GATE          | 7.623T   | 462.585M  | 4.543s  | 37.048                    |

The latency is tested on an NVIDIA 1080TI, MACs and Params are calculated with [calflops](https://github.com/MrYxJ/calculate-flops.pytorch), and the FID is calculated with [PytorchFID](https://github.com/mseitzer/pytorch-fid).