Note. This is a replica PR of #155901 which will be closed. I had to create a new PR in order to add it into my ghstack as there are some later commits which depend on it.
### Summary
🚀 This PR moves the prioritized text linker optimization from setup.py to cmake ( and enables by default on Linux aarch64 systems )
This change consolidates what was previously manual CI logic into a single location (cmake), ensuring consistent behavior across local builds, CI pipelines, and developer environments.
### Motivation
Prioritized text layout has measurable performance benefits on Arm systems by reducing code padding and improving cache utilization. This optimization was previously triggered manually via CI scripts (.ci/aarch64_linux/aarch64_ci_build.sh) or user-set environment variables. By detecting the target architecture within setup.py, this change enables the optimization automatically where applicable, improving maintainability and usability.
Note:
Due to ninja/cmake graph generation issues we cannot apply the linker file globally to all targets to the targets must be manually defined. See CMakeLists.txt the main libraries torch_python, torch, torch_cpu, torch_cuda, torch_xpu have been targetted which should be enough to maintain the performance benefits outlined above.
Co-authored-by: Usamah Zaheer <usamah.zaheer@arm.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/160078
Approved by: https://github.com/seemethere
Note. This is a replica PR of #155901 which will be closed. I had to create a new PR in order to add it into my ghstack as there are some later commits which depend on it.
### Summary
🚀 This PR moves the prioritized text linker optimization from setup.py to cmake ( and enables by default on Linux aarch64 systems )
This change consolidates what was previously manual CI logic into a single location (cmake), ensuring consistent behavior across local builds, CI pipelines, and developer environments.
### Motivation
Prioritized text layout has measurable performance benefits on Arm systems by reducing code padding and improving cache utilization. This optimization was previously triggered manually via CI scripts (.ci/aarch64_linux/aarch64_ci_build.sh) or user-set environment variables. By detecting the target architecture within setup.py, this change enables the optimization automatically where applicable, improving maintainability and usability.
Note:
Due to ninja/cmake graph generation issues we cannot apply the linker file globally to all targets to the targets must be manually defined. See CMakeLists.txt the main libraries torch_python, torch, torch_cpu, torch_cuda, torch_xpu have been targetted which should be enough to maintain the performance benefits outlined above.
Co-authored-by: Usamah Zaheer <usamah.zaheer@arm.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/160078
Approved by: https://github.com/seemethere
This PR adds a linker script optimization based on prioritized symbols that can be extracted from the profiles of popular workloads. The present linker script was generated to target ARM+CUDA and later can be extended if necessary. The reason we target ARM is shown below:
> PyTorch and other applications that access more than 24x 2MB code regions in quick succession can result in performance bottlenecks in the CPU front-end. The link-time optimization improves executable code locality and improve performance. We recommend turning on the optimization always for PyTorch and other application that behaves similarly.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121975
Approved by: https://github.com/ptrblck, https://github.com/atalman
