torch.compiler¶
torch.compiler
is a namespace through which some of the internal compiler
methods are surfaced for user consumption. The main function and the feature in
this namespace is torch.compile
.
torch.compile
is a PyTorch function introduced in PyTorch 2.x that aims to
solve the problem of accurate graph capturing in PyTorch and ultimately enable
software engineers to run their PyTorch programs faster. torch.compile
is
written in Python and it marks the transition of PyTorch from C++ to Python.
torch.compile
leverages the following underlying technologies:
TorchDynamo (torch._dynamo) is an internal API that uses a CPython feature called the Frame Evaluation API to safely capture PyTorch graphs. Methods that are available externally for PyTorch users are surfaced through the
torch.compiler
namespace.TorchInductor is the default
torch.compile
deep learning compiler that generates fast code for multiple accelerators and backends. You need to use a backend compiler to make speedups throughtorch.compile
possible. For NVIDIA and AMD GPUs, it leverages OpenAI Triton as the key building block.AOT Autograd captures not only the user-level code, but also backpropagation, which results in capturing the backwards pass “ahead-of-time”. This enables acceleration of both forwards and backwards pass using TorchInductor.
Note
In some cases, the terms torch.compile
, TorchDynamo, torch.compiler
might be used interchangeably in this documentation.
As mentioned above, to run your workflows faster, torch.compile
through
TorchDynamo requires a backend that converts the captured graphs into a fast
machine code. Different backends can result in various optimization gains.
The default backend is called TorchInductor, also known as inductor,
TorchDynamo has a list of supported backends developed by our partners,
which can be see by running torch.compiler.list_backends()
each of which
with its optional dependencies.
Some of the most commonly used backends include:
Training & inference backends
Backend |
Description |
---|---|
|
Uses the TorchInductor backend. Read more |
|
CUDA graphs with AOT Autograd. Read more |
|
Uses IPEX on CPU. Read more |
|
Uses ONNX Runtime for training on CPU/GPU. Read more |
Inference-only backends
Backend |
Description |
---|---|
|
Uses Torch-TensorRT for inference optimizations. Requires |
|
Uses IPEX for inference on CPU. Read more |
|
Uses Apache TVM for inference optimizations. Read more |
|
Uses OpenVINO for inference optimizations. Read more |
Read More¶
- Getting Started
- torch.compiler API reference
- TorchDynamo APIs for fine-grained tracing
- AOTInductor: Ahead-Of-Time Compilation for Torch.Export-ed Models
- TorchInductor GPU Profiling
- Profiling to understand torch.compile performance
- Frequently Asked Questions
- PyTorch 2.0 Troubleshooting
- PyTorch 2.0 Performance Dashboard