Summary:
The previous code would potentially make it smaller if a device with a
lower ID touched it later. Also we should minimize changes to the state
for multi threaded reasons. This just sets up an owned slot for each at
initialization time.
Similar to H2D and D2H, use synchronous mode for large data transfers
beyond a certain size for D2D as well. As with H2D and D2H, this size is
controlled by an env-var.
Summary:
The current implementation of RPC tied everything to device IDs and
forced us to do init / shutdown to manage some global state. This turned
out to be a bad idea in situations where we want to track multiple
hetergeneous devices that may report the same device ID in the same
process.
This patch changes the interface to instead create an opaque handle to
the internal device and simply allocates it via `new`. The user will
then take this device and store it to interface with the attached
device. This interface puts the burden of tracking the device identifier
to mapped d evices onto the user, but in return heavily simplifies the
implementation.
Summary:
The plan is to remove the entire plugin interface and simply use the
`GenericPluginTy` inside of `libomptarget` by statically linking against
it. This means that inside of `libomptarget` we will simply do
`Plugin.data_alloc` without the dynamically loaded interface. To reduce
the amount of code required, this patch simply moves all of the RTL
implementation functions inside of the Generic device. Now the
`__tgt_rtl_` interface is simply a shallow wrapper that will soon go
away. There is some redundancy here, this will be improved later. For
now what is important is minimizing the changes to the API.
Summary:
We have a plugin singleton that implements the Plugin interface. This
then spawns separate device and kernels. Previously when these needed to
reach into the global singleton they would use the `PluginTy::get`
routine to get access to it. In the future we will move away from this
as the lifetime of the plugin will be handled by `libomptarget`
directly. This patch removes uses of this inside of the plugin
implementaion themselves by simply keeping a reference to the plugin
inside of the device.
The external `__tgt_rtl` functions still use the global method, but will
be removed later.
Summary:
This patch factors common functions out of the `Plugin` interface prior
to its removal in a future patch. This simply temporarily renames it to
`PluginTy` so that we could re-use `Plugin::check` internally as this
needs to be defined statically per plugin now. We can refactor this
later.
The future patch will delete `PluginTy` and `PluginTy::get` entirely.
This simply tries to minimize a few changes to make it easier to land.
Summary:
It's possible for the OpenMP offloading plugins to be build before
tablegen is run despite the fact that we rely on it. Simply make it
depend on it currently.
Use `LINK_COMPONENTS` parameter of `add_llvm_library` rather than
passing LLVM components directly to `target_link_libraries`, in order to
ensure that LLVM dylib is linked correctly when used. Otherwise, CMake
insists on linking to static libraries that aren't present on
distributions doing pure dylib installs, such as Gentoo.
This fixes a regression introduced
in dcbddc2525.
Summary:
This patch reworks the CMake handling for building plugins. All this
does is pull a lot of shared and common logic into a single helper
function.
This also simplifies the OMPT libraries from being built separately
instead of just added.
Commit a7d5f73a03 introduced an
error in a target_compile_definitions on the SystemZ, causing
the build to break. Fixed by adding the missing "PRIVATE".
Summary:
All of these CPU targets use the same underlying implementation. We
should consolidate them into a single target to make it easier to update
this to a static library based approach. I have decided to call this the
'host' target so it can be given a single name. We still only build
these if the system processor matches and we are on Linux.
This patch updates the construction of packet headers to replace the
usage of ACQUIRE/RELEASE with SCACQUIRE/SCRELEASE which is now
recommended.
The patch also ensures consistency across kernel dispatches.
A kernel implicit parameter (dyn_ptr) was introduced some time back.
This patch increments the kernel args version for a compiler supporting
dyn_ptr. The version will be used by the runtime to determine whether
the implicit parameter is generated by the compiler. The versioning is
required to support use cases where code generated by an older compiler
is linked with a newer runtime.
If approved, this patch should be backported to release 18.
The plugin was not getting built as the build_generic_elf64 macro
assumes the LLVM triple processor name matches the CMake processor name,
which is unfortunately not the case for SystemZ.
Fix this by providing two separate arguments instead.
Actually building the plugin exposed a number of other issues causing
various test failures. Specifically, I've had to add the SystemZ target
to
- CompilerInvocation::ParseLangArgs
- linkDevice in ClangLinuxWrapper.cpp
- OMPContext::OMPContext (to set the device_kind_cpu trait)
- LIBOMPTARGET_ALL_TARGETS in libomptarget/CMakeLists.txt
- a check_plugin_target call in libomptarget/src/CMakeLists.txt
Finally, I've had to set a number of test cases to UNSUPPORTED on
s390x-ibm-linux-gnu; all these tests were already marked as UNSUPPORTED
for x86_64-pc-linux-gnu and aarch64-unknown-linux-gnu and are failing on
s390x for what seem to be the same reason.
In addition, this also requires support for BE ELF files in
plugins-nextgen: https://github.com/llvm/llvm-project/pull/85246
Code in plugins-nextgen reading ELF files is currently hard-coded to
assume a 64-bit little-endian ELF format. Unfortunately, this assumption
is even embedded in the interface between GlobalHandler and Utils/ELF
routines, which use ELF64LE types.
To fix this, I've refactored the interface to use generic types, in
particular by using (a unique_ptr to) ObjectFile instead of
ELF64LEObjectFile, and ELFSymbolRef instead of ELF64LE::Sym.
This allows properly templating over multiple ELF format variants inside
Utils/ELF; specifically, this patch adds support for 64-bit big-endian
ELF files in addition to 64-bit little-endian files.
Code in plugins-nextgen reading ELF files is currently hard-coded to
assume a 64-bit little-endian ELF format. Unfortunately, this assumption
is even embedded in the interface between GlobalHandler and Utils/ELF
routines, which use ELF64LE types.
To fix this, I've refactored the interface to use generic types, in
particular by using (a unique_ptr to) ObjectFile instead of
ELF64LEObjectFile, and ELFSymbolRef instead of ELF64LE::Sym.
This allows properly templating over multiple ELF format variants inside
Utils/ELF; specifically, this patch adds support for 64-bit big-endian
ELF files in addition to 64-bit little-endian files.
After 3ecd38c8e, the Handler.getELFObjectFile routine is no
longer available. Call ELF64LEObjectFile::create directly,
which should always be suitable for CUDA images.
The plugin was not getting built as the build_generic_elf64 macro
assumes the LLVM triple processor name matches the CMake processor name,
which is unfortunately not the case for SystemZ.
Fix this by providing two separate arguments instead.
Actually building the plugin exposed a number of other issues causing
various test failures. Specifically, I've had to add the SystemZ target
to
- CompilerInvocation::ParseLangArgs
- linkDevice in ClangLinuxWrapper.cpp
- OMPContext::OMPContext (to set the device_kind_cpu trait)
- LIBOMPTARGET_ALL_TARGETS in libomptarget/CMakeLists.txt
- a check_plugin_target call in libomptarget/src/CMakeLists.txt
Finally, I've had to set a number of test cases to UNSUPPORTED on
s390x-ibm-linux-gnu; all these tests were already marked as UNSUPPORTED
for x86_64-pc-linux-gnu and aarch64-unknown-linux-gnu and are failing on
s390x for what seem to be the same reason.
In addition, this also requires support for BE ELF files in
plugins-nextgen: https://github.com/llvm/llvm-project/pull/83976
Code in plugins-nextgen reading ELF files is currently hard-coded to
assume a 64-bit little-endian ELF format. Unfortunately, this assumption
is even embedded in the interface between GlobalHandler and Utils/ELF
routines, which use ELF64LE types.
To fix this, I've refactored the interface to push all ELF specific
types into Utils/ELF. Specifically, this patch removes both the
getSymbol and getSymbolAddress routines and replaces them with a
single findSymbolInImage, which gets a StringRef identifying the
raw object file image as input, and returns a StringRef covering
the data addressed by the symbol (address and size) if found, or
std::nullopt otherwise.
This allows properly templating over multiple ELF format variants inside
Utils/ELF; specifically, this patch adds support for 64-bit big-endian
ELF files in addition to 64-bit little-endian files.
Summary:
We use `add_llvm_library` as a shorthand for setting up all the
dependencies and libraries we need for the OpenMP offloading runtime as
they depend on a lot of the LLVM utilities. However, we always
explicitly installed these manually. Behind the scenes the function
would then install it again. This was unnoticed because until now the
destinations matched. Now that we want it to optionally go into the
other directory it is duplicating them. Fix this by stating that this is
a build tree only library so we can handle it ourselves.
Summary:
This directory is leftover from when we handled both AMDGPU and NVPTX in
the same build and merged them into a pseudo triple. Now the only thing
it contains is the RPC server header. This gets rid of it, but now that
it's in the base install directory we should make it clear that it's an
LLVM libc header.
Summary:
This is a massive patch because it reworks the entire build and
everything that depends on it. This is not split up because various bots
would fail otherwise. I will attempt to describe the necessary changes
here.
This patch completely reworks how the GPU build is built and targeted.
Previously, we used a standard runtimes build and handled both NVPTX and
AMDGPU in a single build via multi-targeting. This added a lot of
divergence in the build system and prevented us from doing various
things like building for the CPU / GPU at the same time, or exporting
the startup libraries or running tests without a full rebuild.
The new appraoch is to handle the GPU builds as strict cross-compiling
runtimes. The first step required
https://github.com/llvm/llvm-project/pull/81557 to allow the `LIBC`
target to build for the GPU without touching the other targets. This
means that the GPU uses all the same handling as the other builds in
`libc`.
The new expected way to build the GPU libc is with
`LLVM_LIBC_RUNTIME_TARGETS=amdgcn-amd-amdhsa;nvptx64-nvidia-cuda`.
The second step was reworking how we generated the embedded GPU library
by moving it into the library install step. Where we previously had one
`libcgpu.a` we now have `libcgpu-amdgpu.a` and `libcgpu-nvptx.a`. This
patch includes the necessary clang / OpenMP changes to make that not
break the bots when this lands.
We unfortunately still require that the NVPTX target has an `internal`
target for tests. This is because the NVPTX target needs to do LTO for
the provided version (The offloading toolchain can handle it) but cannot
use it for the native toolchain which is used for making tests.
This approach is vastly superior in every way, allowing us to treat the
GPU as a standard cross-compiling target. We can now install the GPU
utilities to do things like use the offload tests and other fun things.
Some certain utilities need to be built with
`--target=${LLVM_HOST_TRIPLE}` as well. I think this is a fine
workaround as we
will always assume that the GPU `libc` is a cross-build with a
functioning host.
Depends on https://github.com/llvm/llvm-project/pull/81557
Summary:
This function is always false in the current implementation and is not
even considered required. Just remove it and if someone needs it in the
future they can add it back in. This is done to simplify the interface
prior to other changes
Summary:
This patch removes the bulk of the handling of the
`__tgt_offload_entries` out of the plugins itself. The reason for this
is because the plugins themselves should not be handling this
implementation detail of the OpenMP runtime. Instead, we expose two new
plugin API functions to get the points to a device pointer for a global
as well as a kernel type.
This required introducing a new type to represent a binary image that
has been loaded on a device. We can then use this to load the addresses
as needed. The creation of the mapping table is then handled just in
`libomptarget` where we simply look up each address individually. This
should allow us to expose these operations more generically when we
provide a separate API.
This patch enables applications that did not request OpenMP
unified_shared_memory to run with the same zero-copy behavior, where
mapped memory does not result in extra memory allocations and memory
copies, but CPU-allocated memory is accessed from the device. The name
for this behavior is "automatic zero-copy" and it relies on detecting:
that the runtime is running on a MI300A, that the user did not select
unified_shared_memory in their program, and that XNACK (unified memory
support) is enabled in the current GPU configuration. If all these
conditions are met, then automatic zero-copy is triggered.
This patch also introduces an environment variable OMPX_APU_MAPS that,
if set, triggers automatic zero-copy also on non APU GPUs (e.g., on
discrete GPUs).
This patch is still missing support for global variables, which will be
provided in a subsequent patch.
Co-authored-by: Thorsten Blass <thorsten.blass@amd.com>
Summary:
This patch is an attempt to make the `find_package(FFI)` support in LLVM
prefer to provide the static library version if present. This is
currently
an optional library for building `libffi`, and its presence implies that
it should likely be used. This patch is an attempt to fix some problems
observed with testing programs linked against `libffi` on many different
systems that could have conflicting paths. Linking it statically
prevents this.
This patch adds the `ffi_static` target for this library.
Summary:
This patch cleans up some of the JIT handling for AMDGPU as well as
removing its temporary files. Previously these would be left in the
temporary directory after the program was run. This costs some extra
time, but the correct solution to avoid that is to create a sufficient
entrypoint into `ld.lld` that we can simply pass a memory buffer into.
Summary:
The constructors and destructors look up a symbol in the ELF quickly to
determine if they need to be run on the GPU. This allows us to avoid the
very slow actions required to do the slower lookup using the vendor API.
One problem occurs with how we handle the lifetime of these images.
Right now there is no invariant to specify the lifetime of the
underlying binary image that is loaded. In the typical case, this comes
from the binary itself in the `.llvm.offloading` section, meaning that
the lifetime of the binary should match the executable itself. This
would work fine, if it weren't for the fact that the plugin is loaded
via `dlopen` and can have a teardown order out of sync with the main
executable.
This was likely what was occuring when this failed on some systems but
not others. A potential solution would be to simply copy images into
memory so the runtime does not rely on external references. Another
would be to manually zero these out after initialization as to prevent
this mistake from happening accidentally. The former has the benefit of
making some checks easier, and allowing for constant initialization be
done on the ELF itself (normally we can't do this because writing to a
constant section, e.g. .llvm.offloading is a segfault.). The downside
would be the extra time required to copy the image in bulk (Although we
are likely doing this in the vendor runtimes as well).
This patch went with a quick solution to simply set a boolean value at
initialization time if we need to call destructors.
Fixes: https://github.com/llvm/llvm-project/issues/77798
Summary:
Recently a patch added an assertion in the GlobalHandler to indicate
when an ELF was not used. This began to fire whenever NVPTX JIT was
used, because the JIT pass output a PTX file instead of an ELF. The
CUModuleLoad method consumes `.s` internally and compiles it to a cubin,
however, this is too late as we perform several checks on the ELF
directly for the presence of certain symbols and to read some necessary
constants. This results in inconsistent behaviour.
To address this, this patch simply calls `ptxas` manually, similar to
how `lld` is called for the AMDGPU JIT pass. This is inevitably going to
be slower than simply passing it to the CUDA routine due to the overhead
involved in file IO and a fork call, but it's necessary for correctness.
CUDA provides an API for compiling PTX manually. However, this only
started showing up in CUDA 11.1 and is only provided "officially" in a
static library. The `libnvidia-ptxjitcompiler.so` next to the CUDA
driver has the same symbols and can likely be used as a replacement.
This would be the faster solution. However, given that it's not
documented it may have some issues.
Summary:
The current code logic is supposed to skip plugins that aren't found or
could not be loaded. However, the plugic ontained a call to `abort` if
it failed, which prevented us from continuing if initilalization the
plugin failed (such as if `dlopen` failed for the dyanmic plugins).
Summary:
The LLVM style uses /*Foo=*/ when indicating the name of a constant. See
https://llvm.org/docs/CodingStandards.html#comment-formatting. This is
useful for consistency, as well as because `clang-format` understands
this syntax and formats it more cleanly. Do a bulk update of this
syntax.
Summary:
The previous behaviour before I made it dynamically open libFFI was that
these tests would be ignored if FFI was not found. This now allows tests
to be run without the dependency and thus the tests fails on some
buildbots. This simply makesit not build the tests if it's not present.
Summary:
The CPU targets currently rely on `libffi` to invoke the "kernel"
functions. Previously we would not build these if this dependency was
not found. This patch copies th eapproach used for things like CUDA and
HSA to dynamically load this if it is not found.
The one sketchy thing this does is hard-code the default ABI for the
target. These are normally defined on a per-file basis in the FFI
source, so I had to fish out the expected values. We only use two types,
so ideally we will always be able to use the default ABI.
It's possible we could remove this dependency entirely in the future as
well.
