Summary:
This pull request has changes for:
1. Enabling a torch module with HIP code to be compiled by cpp_extensions.py
2. Fixes for hipify module to be able to be used by a torch extension
cc: ezyang iotamudelta jeffdaily
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32669
Differential Revision: D20033893
Pulled By: zou3519
fbshipit-source-id: fd6ddc8cdcd3930f41008636bb2bc9dd26cdb008
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32495
Background
------------------------------
Previously, ninja was used to compile+link inline cpp_extensions and
ahead-of-time cpp_extensions were compiled with distutils. This PR adds
the ability to compile (but not link) ahead-of-time cpp_extensions with ninja.
The main motivation for this is to speed up cpp_extension builds: distutils
does not make use of parallelism. With this PR, using the new option, on my machine,
- torchvision compilation goes from 3m43s to 49s
- nestedtensor compilation goes from 2m0s to 28s.
User-facing changes
------------------------------
I added a `use_ninja` flag to BuildExtension. This defaults to
`True`. When `use_ninja` is True:
- it will attempt to use ninja.
- If we cannot use ninja, then this throws a warning and falls back to
distutils.
- Situations we cannot use ninja: Windows (NYI, I'll open a new issue
for this), if ninja cannot be found on the system.
Implementation Details
------------------------------
This PR makes this change in two steps. Please me know if it would be
easier to review this if I split this up into a stacked diff.
Those changes are:
1) refactor _write_ninja_file to separate the policy (what compiler flags
to pass) from the mechanism (how to write the ninja file and do compilation).
2) call _write_ninja_file and _run_ninja_build while building
ahead-of-time cpp_extensions. These are only used to compile objects;
distutils still handles the linking.
Change 1: refactor _write_ninja_file to seperate policy from mechanism
- I split _write_ninja_file into: _write_ninja_file and
_write_ninja_file_to_build_library
- I renamed _build_extension_module to _run_ninja_build
Change 2: Call _write_ninja_file while building ahead-of-time
cpp_extensions
- _write_ninja_file_and_compile_objects calls _write_ninja_file to only
build object files.
- We monkey-patch distutils.CCompiler.compile to call
_write_ninja_files_and_compile_objects
- distutils still handles the linking step. The linking step is not a
bottleneck so it was not a concern.
- This change only works on unix-based systems. Our code for windows
goes down a different codepath and I did not want to mess with that.
- If a system does not support ninja, we raise a warning and fall back
to the original compilation path.
Test Plan
------------------------------
Adhoc testing
- I built torchvision using pytorch master and printed out the build
commands. Next, I used this branch to build torchvision and looked at
the ninja file. I compared the ninja file with the build commands and
asserted that they were functionally the same.
- I repeated the above for pytorch/nestedtensor.
PyTorch test suite
- I split `test_cpp_extensions` into `test_cpp_extensions_aot` and
`test_cpp_extensions_jit`. The AOT (ahead-of-time) version tests
ahead-of-time and the JIT version tests just-in-time (not to be confused
with TorchScript)
- `test_cpp_extensions_aot` gets run TWICE by run_test.py, once with
a module that was built with ninja, and once with a module that was
built without ninja.
- run_test.py asserts that when we are building with use_ninja=True,
ninja is actually available on the system.
Test Plan: Imported from OSS
Differential Revision: D19730432
Pulled By: zou3519
fbshipit-source-id: 819590d01cf65e8da5a1e8019b8b3084792fee90
