Summary:
The previous offloading entry type did not fit the current use-cases
very well. This widens it and adds a version to prevent further
annoyances. It also includes the kind to better sort who's using it.
The first 64-bytes are reserved as zero so the OpenMP runtime can detect
the old format for binary compatibilitry.
Summary:
This patch is an NFC renaming to make using the offloading entry type
more portable between other targets. Right now this is just moving its
definition to LLVM so others can use it. Future work will rework the
struct layout.
We had three `utils::` namespaces, all with different "meaning" (host,
device, hsa_utils). We should, when we can, keep "include/Shared"
accessible from host and device, thus RefCountTy has been moved to a
separate header. `hsa_utils` was introduced to make `utils::` less
overloaded. And common functionality was de-duplicated, e.g.,
`utils::advance` and `utils::advanceVoidPtr` -> `utils:advancePtr`. Type
punning now checks for the size of the result to make sure it matches
the source type.
No functional change was intended.
When we use the device, e.g., with an API that interacts with it, we
need to ensure the image is loaded and the constructors are executed.
Two tests are included to verify we 1) load images and run constructors
when needed, and 2) we do so lazily only if the device is actually used.
---------
Co-authored-by: Joseph Huber <huberjn@outlook.com>
Through the new `-foffload-via-llvm` flag, CUDA kernels can now be
lowered to the LLVM/Offload API. On the Clang side, this is simply done
by using the OpenMP offload toolchain and emitting calls to `llvm*`
functions to orchestrate the kernel launch rather than `cuda*`
functions. These `llvm*` functions are implemented on top of the
existing LLVM/Offload API.
As we are about to redefine the Offload API, this wil help us in the
design process as a second offload language.
We do not support any CUDA APIs yet, however, we could:
https://www.osti.gov/servlets/purl/1892137
For proper host execution we need to resurrect/rebase
https://tianshilei.me/wp-content/uploads/2021/12/llpp-2021.pdf
(which was designed for debugging).
```
❯❯❯ cat test.cu
extern "C" {
void *llvm_omp_target_alloc_shared(size_t Size, int DeviceNum);
void llvm_omp_target_free_shared(void *DevicePtr, int DeviceNum);
}
__global__ void square(int *A) { *A = 42; }
int main(int argc, char **argv) {
int DevNo = 0;
int *Ptr = reinterpret_cast<int *>(llvm_omp_target_alloc_shared(4, DevNo));
*Ptr = 7;
printf("Ptr %p, *Ptr %i\n", Ptr, *Ptr);
square<<<1, 1>>>(Ptr);
printf("Ptr %p, *Ptr %i\n", Ptr, *Ptr);
llvm_omp_target_free_shared(Ptr, DevNo);
}
❯❯❯ clang++ test.cu -O3 -o test123 -foffload-via-llvm --offload-arch=native
❯❯❯ llvm-objdump --offloading test123
test123: file format elf64-x86-64
OFFLOADING IMAGE [0]:
kind elf
arch gfx90a
triple amdgcn-amd-amdhsa
producer openmp
❯❯❯ LIBOMPTARGET_INFO=16 ./test123
Ptr 0x155448ac8000, *Ptr 7
Ptr 0x155448ac8000, *Ptr 42
```
The kernel names for OpenMP are manually mangled and not ideal when we
report something to the user. We demangle them now, providing the
function and line number of the target region, together with the actual
kernel name.
As a first step towards a GPU sanitizer we now can track allocations and
deallocations in order to report double frees, and other problems during
deallocation.
The `llvm-omp-device-info` tool is very handy, but broke due to the lazy
evaluation of devices. This repairs the functionality and adds a test.
The tool is also renamed into `llvm-offload-device-info` as `-omp-` is
going away.
Summary:
Currently, we register images into a linear table according to the
logical OpenMP device identifier. We then initialize all of these images
as one block. This logic requires that images are compatible with *all*
devices instead of just the one that it can run on. This prevents us
from running on systems with heterogeneous devices (i.e. image 1 runs on
device 0 image 0 runs on device 1).
This patch reworks the logic by instead making the compatibility check a
per-device query. We then scan every device to see if it's compatible
and do it as they come.
Summary:
There was a bug here where we would initialize the plugin multiple times
when there were multiple images. Fix it by putting the `is_initliaized`
check later.
Summary:
Initializing the plugins requires initializing the runtime like CUDA or
HSA. This has a considerable overhead on most platforms, so we should
only actually initialize a plugin if it is needed by any image that is
loaded.
Summary:
This isn't `libomptarget` anymore, and these messages were always
unnecessary because no other project uses these prefixed messages. The
effect of this is that no longer will the logs have `LIBOMPTARGET --` in
front of everything. We have a message stating when we start building
the offload project so it'll still be trivial to find.
Summary:
No other project has these in the CMake itself, and they're wildly
inconsistent even within the project. These don't really add anything so
I think they should be removed.
Summary:
A runtime library should not have global constructors. Everything is now
expected to go through the init methods. This patch ensures that global
constructors will not accidentally be introduced.
Summary:
Currently this is only used for the zero-copy handling. However, this
can easily be moved into `libomptarget` so that we do not need to bother
setting the requires flags in the plugin. The advantage here is that we
no longer need to do this for every device redundently. Additionally,
these requires flags are specifically OpenMP related, so they should
live in `libomptarget`.
This patch overhauls the `libomptarget` and plugin interface. Currently,
we define a C API and compile each plugin as a separate shared library.
Then, `libomptarget` loads these API functions and forwards its internal
calls to them. This was originally designed to allow multiple
implementations of a library to be live. However, since then no one has
used this functionality and it prevents us from using much nicer
interfaces. If the old behavior is desired it should instead be
implemented as a separate plugin.
This patch replaces the `PluginAdaptorTy` interface with the
`GenericPluginTy` that is used by the plugins. Each plugin exports a
`createPlugin_<name>` function that is used to get the specific
implementation. This code is now shared with `libomptarget`.
There are some notable improvements to this.
1. Massively improved lifetimes of life runtime objects
2. The plugins can use a C++ interface
3. Global state does not need to be duplicated for each plugin +
libomptarget
4. Easier to use and add features and improve error handling
5. Less function call overhead / Improved LTO performance.
Additional changes in this plugin are related to contending with the
fact that state is now shared. Initialization and deinitialization is
now handled correctly and in phase with the underlying runtime, allowing
us to actually know when something is getting deallocated.
Depends on https://github.com/llvm/llvm-project/pull/86971https://github.com/llvm/llvm-project/pull/86875https://github.com/llvm/llvm-project/pull/86868
This patch overhauls the `libomptarget` and plugin interface. Currently,
we define a C API and compile each plugin as a separate shared library.
Then, `libomptarget` loads these API functions and forwards its internal
calls to them. This was originally designed to allow multiple
implementations of a library to be live. However, since then no one has
used this functionality and it prevents us from using much nicer
interfaces. If the old behavior is desired it should instead be
implemented as a separate plugin.
This patch replaces the `PluginAdaptorTy` interface with the
`GenericPluginTy` that is used by the plugins. Each plugin exports a
`createPlugin_<name>` function that is used to get the specific
implementation. This code is now shared with `libomptarget`.
There are some notable improvements to this.
1. Massively improved lifetimes of life runtime objects
2. The plugins can use a C++ interface
3. Global state does not need to be duplicated for each plugin +
libomptarget
4. Easier to use and add features and improve error handling
5. Less function call overhead / Improved LTO performance.
Additional changes in this plugin are related to contending with the
fact that state is now shared. Initialization and deinitialization is
now handled correctly and in phase with the underlying runtime, allowing
us to actually know when something is getting deallocated.
Depends on https://github.com/llvm/llvm-project/pull/86971https://github.com/llvm/llvm-project/pull/86875https://github.com/llvm/llvm-project/pull/86868
Summary:
The `GenericDeviceTy::dataDelete` method doesn't verify the
`TargetAllocTy` of the of the device pointer. Because of this, it can
use the `MemoryManager` to free the ptr. However, the
`TARGET_ALLOC_HOST` and `TARGET_ALLOC_SHARED` types are not allocated
using the `MemoryManager` in the `GenericDeviceTy::dataAlloc` method.
Since the `MemoryManager` uses the `DeviceAllocatorTy::free` operation
without specifying the type of the ptr, some plugins may use incorrect
operations to free ptrs of certain types. In particular, this bug causes
the CUDA plugin to use the `cuMemFree` operation on ptrs of type
`TARGET_ALLOC_HOST`, resulting in an unchecked error, as shown in the
output snippet of the test
`offload/test/api/omp_host_pinned_memory_alloc.c`:
```
omptarget --> Notifying about an unmapping: HstPtr=0x00007c6114200000
omptarget --> Call to llvm_omp_target_free_host for device 0 and address 0x00007c6114200000
omptarget --> Call to omp_get_num_devices returning 1
omptarget --> Call to omp_get_initial_device returning 1
PluginInterface --> MemoryManagerTy:🆓 target memory 0x00007c6114200000.
PluginInterface --> Cannot find its node. Delete it on device directly.
TARGET CUDA RTL --> Failure to free memory: Error in cuMemFree[Host]: invalid argument
omptarget --> omp_target_free deallocated device ptr
```
This patch fixes this by adding the check of the device pointer type
before calling the appropriate operation for each type.
Summary:
Previously we would build all of the plugins by default and then only
load some using the `LIBOMPTARGET_PLUGINS_TO_LOAD` variable. This patch
renamed this to `LIBOMPTARGET_PLUGINS_TO_BUILD` and changes whether or
not it will include the plugin in CMake.
Additionally this patch creates a new `Targets.def` file that allows us
to enumerate all of the enabled plugins. This is somewhat different from
the old method, and it's done this way for future use that will need to
be shared. This follows the same method that LLVM uses for its targets,
however it does require adding an extra include path.
Depends on https://github.com/llvm/llvm-project/pull/86868
Summary:
All of these are functionally the same code, just compiled for separate
architectures. We currently do not expose a way to execute these on
separate architectures as the host plugin works using `dlopen` into the
same process, and therefore cannot possibly be an incompatible
architecture. (This could work with a remote plugin, but this is not
supported yet).
This patch simply renames all of these to the same thing so we no longer
need to check around for its varying definitions.
In a nutshell, this moves our libomptarget code to populate the offload
subproject.
With this commit, users need to enable the new LLVM/Offload subproject
as a runtime in their cmake configuration.
No further changes are expected for downstream code.
Tests and other components still depend on OpenMP and have also not been
renamed. The results below are for a build in which OpenMP and Offload
are enabled runtimes. In addition to the pure `git mv`, we needed to
adjust some CMake files. Nothing is intended to change semantics.
```
ninja check-offload
```
Works with the X86 and AMDGPU offload tests
```
ninja check-openmp
```
Still works but doesn't build offload tests anymore.
```
ls install/lib
```
Shows all expected libraries, incl.
- `libomptarget.devicertl.a`
- `libomptarget-nvptx-sm_90.bc`
- `libomptarget.rtl.amdgpu.so` -> `libomptarget.rtl.amdgpu.so.18git`
- `libomptarget.so` -> `libomptarget.so.18git`
Fixes: https://github.com/llvm/llvm-project/issues/75124
---------
Co-authored-by: Saiyedul Islam <Saiyedul.Islam@amd.com>
