Summary:
Some older compilers, which we still support, have problems handling the
copy elision that allows us to directly move an `Error` to an
`Expected`. This patch adds explicit moves to remove the error.
Summary:
Tihs patch is mostly NFC to fix some warning currently present in OpenMP
offloading plugins. Specifically this mostly removes the use of Twine
variables in favor of LLVM's small string. Twine variables are prone to
use-after-free and this is a cleaner way to concatenate a string.
The next-gen plugins did not properly set the values from
`OMP_NUM_TEAMS` and `OMP_TEAMS_THREAD_LIMIT`. This is because these
maximum values are set by each plugin to its hardware maximum. This
happens *after* the previous initialization. Move it to the correct
place and then add a test.
Fixes https://github.com/llvm/llvm-project/issues/61082
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D145105
Makes the info that is printed for kernel launches configurable for
different plugins. Adds all machinery to print the detailed launch
info that the current AMD plugin provides and includes e.g. register
spill counts.
The files msgpack.cpp, msgpack.def, and msgpack.h are copied from the old plugin
and are untouched. The contents of UtilitiesHSA.cpp and .h are copied together from
various files from the old plugin. The code was originally written by
Jon Chesterfield. I updated the function and type names visible to the outside, i.e.
in headers, to respect the LLVM conventions.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D144521
The NextGen plugins use the information regarding new mapping/unmappings to
lock/unlock the corresponding host buffer and speed up the host-device memory
transfers involving those buffers. The locking/unlocking is disabled by default
and can be enabled by the LIBOMPTARGET_LOCK_MAPPED_HOST_BUFFERS envar. The
envar accepts boolean values (on/off) and a special option:
- off: Do not lock mapped host buffers (default).
- on: Lock mapped host buffers automatically, but do not report lock
failures if the plugin fails to lock them.
- mandatory: Lock mapped host buffers automatically and treat locking failures
in the plugins as fatal errors. This option may be useful for
debugging purposes.
Differential Revision: https://reviews.llvm.org/D142514
This patch implements the memory lock/unlock API, introduced in patch https://reviews.llvm.org/D139208,
in the NextGen plugins. Locked buffers feature reference counting and we allow certain overlapping. Given
an already locked buffer A, other buffers that are fully contained inside A can be locked again, even if
they are smaller than A. In this case, the reference count of locked buffer A will be incremented. However,
extending an existing locked buffer is not allowed. The original buffer is actually unlocked once all its
users have released the locked buffer and sub-buffers (i.e., the reference counter becomes zero).
Differential Revision: https://reviews.llvm.org/D141227
Dynamic memory allows users to allocate fast shared memory when a kernel
is launched. We support a single size for all kernels via the
`LIBOMPTARGET_SHARED_MEMORY_SIZE` environment variable but now we can
control it per kernel invocation, hence allow computed values.
Note: Only the nextgen plugins will allocate memory based on the clause,
the old plugins will silently miscompile.
Differential Revision: https://reviews.llvm.org/D141233
We already created a versioned `__tgt_kernel_arguments` struct but it
was only briefly used and its content was passed in isolation anyway.
This makes it hard to add more information in the future. With this
patch we fully embrace the struct as means to pass information from the
compiler to the plugin as part of a kernel launch.
The patch also extends and renames the struct, bumping the version
number to 2. Version 1 entries are auto-upgraded. This is in preparation
for "bare" kernel launches, per kernel dynamic shared memory, CUDA/HIP
lowering, etc.
The `__tgt_target_kernel_nowait` interface was deprecated as it was
unused. Once we actually implement support for something like that, we
can add an appropriate API.
Note: Only plugins with the `launch_kernel` interface are now supported.
That means that a new clang won't be able to use an old runtime.
An old clang can still use the new runtime since the libomptarget
interface did not change.
Differential Revision: https://reviews.llvm.org/D141232
This patch enables to store bitcode images when JIT is enabled for the record-and-replay functionality (see https://reviews.llvm.org/D138931). Credits to @jdoerfert for refactoring the code.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D141986
This patch adds functionality for recording and replaying the execution of OpenMP offload kernels, based on an original implementation by Steve Rangel. The patch extends libomptarget to extract a json description of the kernel, the device image binary, and a device memory snapshot before and after the execution of a recorded kernel. Kernel recording/replaying in libomptarget is controlled through env vars (LIBOMPTARGET_RECORD, LIBOMPTARGET_REPLAY). It provides a tool, llvm-omp-kernel-replay, for replaying a kernel using the extracted information with the ability to verify replayed execution using the post-execution device memory snapshot, also supporting changing the number of teams/threads for replaying.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D138931
This variable is used by the runtime. Before kernel launch we set it to
indicate several configuration options from the host. This patch renames
it to be more in-line with the rest of the named exported from the
runtime. This is better because this is the only symbol visible to the
host from the runtime, so it should have a reserved name.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D141960
The JIT interface was somewhat irregular as it used multiple global
functions. It also did not cache the results of the JIT, hence multiple
GPU systems would perform the work multiple times. Finally, there might
have been races on the state if we have multi-threaded initialization of
different embedded images, or one image initialized on multiple devices.
This patch tries to rectify all of the above. The JITEngine is now a
part of the GenericPluginTy and tied to one target triple. To support
multiple "ComputeUnitKind"s (previously confusingly called Arch or
[M]CPU) and to avoid re-jitting for the same ComputeUnitKind, we keep a
map of JIT results per ComputeUnitKind. All interaction with the JIT
happens through the JITEngine directly, two functions are exposed. Both
use (shared) locks to avoid races and cache the result. All JIT-related
environment variables are now defined together.
Differential Revision: https://reviews.llvm.org/D141081
We can now dump the IR before and after JIT optimizations into the
files passed via `LIBOMPTARGET_JIT_PRE_OPT_IR_MODULE` and
`LIBOMPTARGET_JIT_POST_OPT_IR_MODULE`, respectively.
Similarly, users can set `LIBOMPTARGET_JIT_REPLACEMENT_MODULE` to
replace the IR in the image with a custom IR module in a file.
All options take file paths, documentation was added.
Reviewed by: tianshilei1992
Differential revision: https://reviews.llvm.org/D140945
Defaulting to Generic mode doesn't make much sense as the kernel needs
to be prepared for it. SPMD mode is the "native" execution, e.g., for
"bare" kernels. It also is the execution method for constructors and
destructors (as we might otherwise throw an extra warp onto them).
Differential Revision: https://reviews.llvm.org/D140718
This patch adds the basic JIT support for OpenMP. Currently it only works on Nvidia GPUs.
The support for AMDGPU can be extended easily by just implementing three interface functions. However, the infrastructure requires a small extra extension (add a pre process hook) to support portability for AMDGPU because the AMDGPU backend reads target features of functions. 02bc7effcc (diff-321c2038035972ad4994ff9d85b29950ba72c08a79891db5048b8f5d46915314R432) shows how it roughly works.
As for the test, even though I added the corresponding code in CMake files, the test still cannot be triggered because some code is missing in the new plugin CMake file, which has nothing to do with this patch. It will be fixed later.
In order to enable JIT mode, when compiling, `-foffload-lto` is needed, and when linking, `-foffload-lto -Wl,--embed-bitcode` is needed. That implies that, LTO is required to enable JIT mode.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D139287
This patch adds the basic JIT support for OpenMP. Currently it only works on Nvidia GPUs.
The support for AMDGPU can be extended easily by just implementing three interface functions. However, the infrastructure requires a small extra extension (add a pre process hook) to support portability for AMDGPU because the AMDGPU backend reads target features of functions. 02bc7effcc (diff-321c2038035972ad4994ff9d85b29950ba72c08a79891db5048b8f5d46915314R432) shows how it roughly works.
As for the test, even though I added the corresponding code in CMake files, the test still cannot be triggered because some code is missing in the new plugin CMake file, which has nothing to do with this patch. It will be fixed later.
In order to enable JIT mode, when compiling, `-foffload-lto` is needed, and when linking, `-foffload-lto -Wl,--embed-bitcode` is needed. That implies that, LTO is required to enable JIT mode.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D139287
This patch moves the management/tracking of host pinned buffers to the common PluginInterface
in NextGen plugins. For the moment, the management consists of tracking the host pinned
allocations into a map in each device.
Differential Revision: https://reviews.llvm.org/D140502
With this patch we:
- pick more sensible defaults for the number of teams, inspired by the
old plugin, and configured via LIBOMPTARGET_AMDGPU_TEAMS_PER_CU.
- check the input signal of a kernel launch late, after the queue lock
was taken, to avoid a barrier packet more often.
- copy the kernel arguments in one swoop into the appropriate memory.
- manually specialize the callbacks to avoid potential indirect calls.
This patch better integrates the target nowait functions with the tasking runtime. It splits the nowait execution into two stages: a dispatch stage, which triggers all the necessary asynchronous device operations and stores a set of post-processing procedures that must be executed after said ops; and a synchronization stage, responsible for synchronizing the previous operations in a non-blocking manner and running the appropriate post-processing functions. Suppose during the synchronization stage the operations are not completed. In that case, the attached hidden helper task is re-enqueued to any hidden helper thread to be later synchronized, allowing other target nowait regions to be concurrently dispatched.
Reviewed By: jdoerfert, tianshilei1992
Differential Revision: https://reviews.llvm.org/D132005
This patch removes the classes GenericStreamManagerTy and GenericEventManagerTy
from the PluginInterface header.
Differential Revision: https://reviews.llvm.org/D138769
This patch modifies the PluginInterface to define functions for initializing
and deinitializing GenericPluginTy instances instead of using the constructor
and destructor. This way, we can return errors from these functions. Also, it
defines some functions that each plugin should implement for creating
plugin-specific objects.
This patch prepares the PluginInterface for the new AMDGPU NextGen plugin.
Differential Revision: https://reviews.llvm.org/D138625
List of fixes:
- omptarget_device_environment symbol is not mandatory in device images
- Do not synchronize in ~AsyncInfoWrapperTy() if the async info's queue is null
- GenericDeviceResourceRef's create() and destroy() require the device as parameter
Differential Revision: https://reviews.llvm.org/D138619
This patch adds a new infrastructure for OpenMP target plugins. It also implements the CUDA and GenericELF64bit plugins under this new infrastructure. We place the sources in a separate directory named plugins-nextgen, and we build the new plugins as different plugin libraries. The original plugins, which remain untouched, will be used by default. However, the user can change this behavior at run-time through the boolean envar LIBOMPTARGET_NEXTGEN_PLUGINS. If enabled, the libomptarget will try to load the NextGen version of each plugin, falling back to the original if they are not present or valid.
The idea of this new plugin infrastructure is to implement the common parts of target plugins in generic classes (defined in files inside plugins-next/common/PluginInterface folder), and then, each specific plugin defines its own specific classes inheriting from the common ones. In this way, most logic remains on the common interface while reducing the plugin-specific source code. It is also beneficial in the sense that now most code and behavior are the same across the different plugins. As an example, we define classes for a plugin, a device, a device image, a stream manager, etc. The plugin object (a single instance per plugin library) holds different device objects (i.e., one per available device), while these latter are the responsible for managing its own resources.
Most code on this patch is based on the changes made by @jdoerfert (Johannes Doerfert)
Reviewed By: jhuber6, jdoerfert
Differential Revision: https://reviews.llvm.org/D134396
