This is equivalent to `cuOccupancyMaxPotentialBlockSize`. It is
currently
only implemented on Cuda; AMDGPU and Host return unsupported.
---------
Co-authored-by: Callum Fare <callum@codeplay.com>
Rather than having every "enqueue"-type function have an output pointer
specifically for an output event, just provide an `olCreateEvent`
entrypoint which pushes an event to the queue.
For example, replace:
```cpp
olMemcpy(Queue, ..., EventOut);
```
with
```cpp
olMemcpy(Queue, ...);
olCreateEvent(Queue, EventOut);
```
`olGetKernel` has been replaced by `olGetSymbol` which accepts a
`Kind` parameter. As well as loading information about kernels, it
can now also load information about global variables.
In the future, we want `ol_symbol_handle_t` to represent both kernels
and global variables The first step in this process is a rename and
promotion to a "typed handle".
This is a three element x, y, z size_t vector that can be used any place
where a 3D vector is required. This ensures that all vectors across
liboffload are the same and don't require any resizing/reordering
dances.
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.
