800d949bb3
Implement the complete initial version of the Offload API, to the extent that is usable for simple offloading programs. Tested with a basic SYCL program. As far as possible, these are simple wrappers over existing functionality in the plugins. * Allocating and freeing memory (host, device, shared). * Creating a program * Creating a queue (wrapper over asynchronous stream resource) * Enqueuing memcpy operations * Enqueuing kernel executions * Waiting on (optional) output events from the enqueue operations * Waiting on a queue to finish Objects created with the API have reference counting semantics to handle their lifetime. They are created with an initial reference count of 1, which can be incremented and decremented with retain and release functions. They are freed when their reference count reaches 0. Platform and device objects are not reference counted, as they are expected to persist as long as the library is in use, and it's not meaningful for users to create or destroy them. Tests have been added to `offload.unittests`, including device code for testing program and kernel related functionality. The API should still be considered unstable and it's very likely we will need to change the existing entry points.
The LLVM/Offload Subproject
The Offload subproject aims at providing tooling, runtimes, and APIs that allow users to execute code on accelerators or other "co-processors" that may or may not match the architecture of their "host". In the long run, all kinds of targets are in scope of this effort, including but not limited to: CPUs, GPUs, FPGAs, AI/ML accelerators, distributed resources, etc.
For OpenMP offload users, the project is ready and fully usable. The final API design is still under development. More content will show up here and on our webpage soon. In the meantime, people are encouraged to participate in our meetings (see below) and check our development board as well as the discussions on Discourse.
Meetings
Every second Wednesday, 7:00 - 8:00am PT, starting Jan 24, 2024. Alternates with the OpenMP in LLVM meeting. invite.ics Meeting Minutes and Agenda