Summary:
If the call to `synchronize` fails, it will currently block the stream indefinitely if execution is continued from this point. Additionally, if the program exits it will trigger an assertion on the non-null value of the async queue and prevent the runtime from printing debugging information.
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D99443
-- Added or moved checks to appropriate places.
-- Removed ineffective null check where the pointer is already being
dereferenced around the code.
-- Initialized variables that can be used without definitions.
-- Added call to dlclose/FreeLibrary in OMPT tool activation.
-- Added a new build compiler definition.
Differential Revision: https://reviews.llvm.org/D98584
It is reported that after enabling hidden helper thread, the program
can hit the assertion `new_gtid < __kmp_threads_capacity` sometimes. The root
cause is explained as follows. Let's say the default `__kmp_threads_capacity` is
`N`. If hidden helper thread is enabled, `__kmp_threads_capacity` will be offset
to `N+8` by default. If the number of threads we need exceeds `N+8`, e.g. via
`num_threads` clause, we need to expand `__kmp_threads`. In
`__kmp_expand_threads`, the expansion starts from `__kmp_threads_capacity`, and
repeatedly doubling it until the new capacity meets the requirement. Let's
assume the new requirement is `Y`. If `Y` happens to meet the constraint
`(N+8)*2^X=Y` where `X` is the number of iterations, the new capacity is not
enough because we have 8 slots for hidden helper threads.
Here is an example.
```
#include <vector>
int main(int argc, char *argv[]) {
constexpr const size_t N = 1344;
std::vector<int> data(N);
#pragma omp parallel for
for (unsigned i = 0; i < N; ++i) {
data[i] = i;
}
#pragma omp parallel for num_threads(N)
for (unsigned i = 0; i < N; ++i) {
data[i] += i;
}
return 0;
}
```
My CPU is 20C40T, then `__kmp_threads_capacity` is 160. After offset,
`__kmp_threads_capacity` becomes 168. `1344 = (160+8)*2^3`, then the assertions
hit.
Reviewed By: protze.joachim
Differential Revision: https://reviews.llvm.org/D98838
Add register usage information to the runtime metadata so that it can be used during kernel launch (that change will be in a different commit). Add this information to the kernel trace.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D98829
[libomptarget] Build amdgcn devicertl by default
The cmake for this looks for an llvm install and does the right thing when
building as part of enable_runtimes. It will probably do the right thing
in other settings - at least, it won't try to build this with gcc.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D98658
[libomptarget] Build amdgpu plugin by default
This will build the amdgpu plugin if cmake is able to find the hsa
runtime library, which will be the case if rocm is installed or if
the hsa library has been installed somewhere cmake looks.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D98654
[libomptarget] Fix devicertl build
The target specific functions in target_interface are extern C, but the
implementations for nvptx were mostly C++ mangling. That worked out as
a quirk of DEVICE macro expanding to nothing, except for shuffle.h which
only forward declared the functions with C++ linkage.
Also implements GetWarpSize, as used by shuffle, and includes target_interface
in nvptx target_impl.cu to help catch future divergence between interface and
implementation.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D98651
[libomptarget] Drop assert.h, use freestanding for amdgcn devicertl
Promotes the runtime assert to a link time error for the unimplemented
fallback functions. Enables amdgcn to build with only clang provided
headers, which makes it less likely to break other builds when enabled.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D98649
[libomptarget][amdgcn] Drop use of inttypes.h, moving closer to freestanding
The glibc headers are a periodic source of problems compiling the devicertl.
This patch resolves the following error run into while building llvm on a slightly
different linux system.
```
In file included from .../lib/clang/13.0.0/include/inttypes.h:21:
In file included from /usr/include/inttypes.h:25:
/usr/include/features.h:461:12: fatal error: 'sys/cdefs.h' file not found
# include <sys/cdefs.h>
^~~~~~~~~~~~~
```
As a second patch, removing assert.h from shuffle will let amdgcn build as
-ffreestanding, at which point only the headers that clang itself provides are
used and interactions with the host glibc are eliminated. Doing the same for
nvptx is complicated by printf handling but also seems worthwhile.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D98565
This patch adds the infrastructure for allocator support for target memory.
Three allocators are introduced for device, host and shared memory.
The corresponding API functions have the llvm_ prefix temporarily, until they become part of the OpenMP standard.
Differential Revision: https://reviews.llvm.org/D97883
The shuffle idiom is differently implemented in our supported targets.
To reduce the "target_impl" file we now move the shuffle idiom in it's
own self-contained header that provides the implementation for AMDGPU
and NVPTX. A fallback can be added later on.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D95752
Summary:
The changes introduced in D87946 changed the API for libomptarget
functions. `__kmpc_push_target_tripcount` was a function in Clang 11.x
but was not given a backward-compatible interface. This change will
require people using Clang 13.x or 12.x to recompile their offloading
programs.
Reviewed By: jdoerfert cchen
Differential Revision: https://reviews.llvm.org/D98358
For clang this change is NFC cleanup, because clang
never calls atomic functions from runtime library.
Basically, pause is good in spin-loops waiting for something.
Atomic CAS loops do not wait for anything,
each CAS failure means some other thread progressed.
Performance experiments show that the pause only causes unnecessary slowdown
on CPUs with slow pause instruction, no difference on CPUs with fast pause
instruction, removal of the pause gives lesser binary size which is good.
Differential Revision: https://reviews.llvm.org/D97079
In D97003, CUDA 9.2 is the minimum requirement for OpenMP offloading on
NVPTX target. We don't need to have macros in source code to select right functions
based on CUDA version. we don't need to compile multiple bitcode libraries of
different CUDA versions for each SM. We don't need to worry about future
compatibility with newer CUDA version.
`-target-feature +ptx61` is used in this patch, which corresponds to the highest
PTX version that CUDA 9.2 can support.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97198
Restrict the chunk_size * chunk_num to only occur for valid
chunk_nums and reimplement calculating the limit to avoid overflow.
Differential Revision: https://reviews.llvm.org/D96747
and __kmpc_end_masked. The "master" construct is deprecated. Changed
proc-bind keyword from "master" to "primary". Use of both master
construct and master as proc-bind keyword is still allowed, but
deprecated.
Remove references to "master" in comments and strings, and replace
with "primary" or "primary thread". Function names and variables were
not touched, nor were references to deprecated master construct. These
can be updated over time. No new code should refer to master.
This patch just encapsulates some repeated code. To do so, it
relocates some functions from interface.cpp to omptarget.cpp. It also
adjusts them to the LLVM coding style.
This patch is almost NFC except some `DP` messages are a bit
different. For example, messages like "Entering target region" are
now emitted even if offload is disabled, but a subsequent "Offload is
disabled" is then emitted.
Reviewed By: jdoerfert, grokos
Differential Revision: https://reviews.llvm.org/D97908
Without this patch, an `omp target exit data` before the runtime is
initialized produces a runtime error. This patch fixes that by
changing `__tgt_target_data_end_mapper` to call `CheckDeviceAndCtors`
like many other runtime routines.
Discussed at
<https://lists.llvm.org/pipermail/openmp-dev/2021-March/003920.html>.
Reviewed By: grokos
Differential Revision: https://reviews.llvm.org/D97907
Without this patch, when the offload device is set to
`omp_get_initial_device()`, the runtime fails with an error diagnostic
when entering target regions or target data regions.
However, OpenMP 5.1, sec. 2.14.5 "target Construct", "Restrictions",
p. 203, L3-5 states:
> The device clause expression must evaluate to a non-negative integer
> value that is less than or equal to the value of
> omp_get_num_devices().
Sec. 3.7.7 "omp_get_initial_device", p. 412, L2-3 states:
> The value of the device number is the value returned by the
> omp_get_num_devices routine.
Similarly, OpenMP 5.0, sec. 2.12.5 "target Construct", "Restrictions",
p. 174 L30-32 states:
> The device clause expression must evaluate to a non-negative integer
> value less than the value of omp_get_num_devices() or to the value
> of omp_get_initial_device().
This patch fixes this behavior by changing the runtime to behave as if
offloading is disabled whenever it finds the offload device (either
from a `device` clause or the default device) is set to the host
device. In the case of mandatory offloading when
`omp_get_num_devices() == 0`, it incorporates the behavior proposed
for OpenMP 5.2 in OpenMP spec github issue 2669.
Reviewed By: grokos, RaviNarayanaswamy
Differential Revision: https://reviews.llvm.org/D97616
This is a preview of allocator support for target memory that depends on the
offload runtime API which allocates memory as described below.
llvm_omp_target_alloc_host(size_t size, int device_num);
-- Returns non-migratable memory owned by host.
-- Memory is accessible by host and device(s).
llvm_omp_target_alloc_shared(size_t size, int device_num);
-- Returns migratable memory owned by host and device.
-- Memory is accessible by host and device.
llvm_omp_target_alloc_device(size_t size, int device_num);
-- Returns memory owned by device.
-- Memory is only accessible by device.
New memory space and predefined allocator names are
-- llvm_omp_target_host_mem_space
-- llvm_omp_target_shared_mem_space
-- llvm_omp_target_device_mem_space
-- llvm_omp_target_host_mem_alloc
-- llvm_omp_target_shared_mem_alloc
-- llvm_omp_target_device_mem_alloc
Differential Revision: https://reviews.llvm.org/D96669
If the mapped structure has data members, which have 'default' mappers,
need to map these members individually using their 'default' mappers.
Differential Revision: https://reviews.llvm.org/D92195
Cleanup changes:
- check value read from file;
- remove dead code;
- make unsigned variable to read hexadecimal number to;
- add debug assertion to check ref count.
Differential Revision: https://reviews.llvm.org/D96893
Stitching id could be overridden causing reference of destroyed object
when number of teams is 1. The patch separates stitching id store
location for teams and parallel nested in teams.
Differential Revision: https://reviews.llvm.org/D96562
Allow users to use a non-system version of perl, python and awk, which is useful
in certain package managers.
Reviewed By: JDevlieghere, MaskRay
Differential Revision: https://reviews.llvm.org/D95119
PR#49334 reports a crash when offloading to x86_64 with `target nowait`,
which is caused by referencing a nullptr. The root cause of the issue is, when
pushing a hidden helper task in `__kmp_push_task`, it also maps the gtid to its
shadow gtid, which is wrong.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97329
This makes sure that images are loaded in the order in which they are registered with libomptarget.
If a target can load multiple images and these images depend on each other (for example if one image contains the programs target regions and one image contains library code), then the order in which images are loaded can be important for symbol resolution (for example, in the VE plugin).
In this case: because the same code exist in the host binaries, the order in which the host linker loads them (which is also the order in which images are registered with libomptarget) is the order in which the images have to be loaded onto the device.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D95530
When including <ostream>, the register_callback macro of the OMPT callback.h
clashes with a function defined in ostream. This patch renames the macro
and includes ompt into the macro name.
`ptx71` is not supported in release version of LLVM yet. As a result,
the support of CUDA 11.2 and CUDA 11.1 caused a compilation error as mentioned
in D97004. Since the support in D97004 is just a WA for releease, and we'll not
use it in the near future, using `ptx70` for CUDA 11 is feasible.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97195
This code alleviates some pathological loop parameters (lower,
upper, stride) within calculations involved in the static loop code. It
bounds the chunk size to the trip count if it is greater than the trip
count and also minimizes problematic code for when trip count < nth.
Differential Revision: https://reviews.llvm.org/D96426
Only attempt shutdown if lpReserved is NULL. The Windows documentation
states:
When handling DLL_PROCESS_DETACH, a DLL should free resources such as
heap memory only if the DLL is being unloaded dynamically (the
lpReserved parameter is NULL). If the process is terminating (the
lpReserved parameter is non-NULL), all threads in the process except the
current thread either have exited already or have been explicitly
terminated by a call to the ExitProcess function, which might leave some
process resources such as heaps in an inconsistent state. In this case,
it is not safe for the DLL to clean up the resources. Instead, the DLL
should allow the operating system to reclaim the memory.
Differential Revision: https://reviews.llvm.org/D96750
This patch limits the number of dispatch buffers (used for
loop worksharing construct) to between 1 and 4096.
Differential Revision: https://reviews.llvm.org/D96749
As mentioned in PR#49250, without this patch, ptxas for CUDA 9.1 fails
in the following two tests:
- openmp/libomptarget/test/mapping/lambda_mapping.cpp
- openmp/libomptarget/test/offloading/bug49021.cpp
The error looks like:
```
ptxas /tmp/lambda_mapping-081ea9.s, line 828; error : Not a name of any known instruction: 'activemask'
```
The problem is that our cmake script converts CUDA version strings
incorrectly: 9.1 becomes 9100, but it should be 9010, as shown in
`getCudaVersion` in `clang/lib/Driver/ToolChains/Cuda.cpp`. Thus,
`openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.cu`
inadvertently enables `activemask` because it apparently becomes
available in 9.2. This patch fixes the conversion.
This patch does not fix the other two tests in PR#49250.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D97012
Without this patch, there's a runtime error for those map types at
exit from an "omp target data" or at "omp target exit data", but the
spec says the list item should be ignored.
This patch tests that fix in data_absent_at_exit.c, and it also
improves other testing for data that is not fully present at exit.
Reviewed By: grokos, RaviNarayanaswamy
Differential Revision: https://reviews.llvm.org/D96999
allow bit masking to select various trace features.
bit 0 => Launch tracing (stderr)
bit 1 => timing of runtime (stdout)
bit 2 => detailed launch tracing (stderr)
bit 3 => timing goes to stdout instead of stderr
example: LIBOMPTARGET_KERNEL_TRACE=7 does it all
LIBOMPTARGET_KERNEL_TRACE=5 Launch + details
LIBOMPTARGET_KERNEL_TRACE=2 timings + launch to stderr
LIBOMPTARGET_KERNEL_TRACE=10 timings + launch to stdout
Differential Revision: https://reviews.llvm.org/D96998
OpenMP 5.0 removed a lot of restriction for overlapped mapped items
comparing to OpenMP 4.5. Patch restricts the checks for overlapped data
mappings only for OpenMP 4.5 and less and reorders mapping of the
arguments so, that present and alloc mappings are processed first and
then all others.
Differential Revision: https://reviews.llvm.org/D86119
As reported by Guilherme Valarini [0], we used to pass stack allocations
to calls that can nowadays be asynchronous. This is arguably a problem
and it will inevitably result in UB. To remedy the situation we
allocate the locations as part of the AsyncInfoTy object. The lifetime
of that object matches what we need for now. If the synchronization is
not tied to the AsyncInfoTy object anymore we might need to have a
different buffer construct in global space.
This should be back-ported to LLVM 12 but needs slight modifications as
it is based on refactoring patches we do not need to backport.
[0] https://lists.llvm.org/pipermail/openmp-dev/2021-February/003867.html
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D96667
This patch unifies our libomptarget API in two ways:
- always pass a `__tgt_async_info` object, the Queue member decides if
it is in use or not.
- (almost) always synchronize in the interface layer and not in the
omptarget layer.
A side effect is that we now put all constructor and static initializer
kernels in a stream too, if the device utilizes `__tgt_async_info`.
The patch contains a TODO which can be addressed as we add support for
asynchronous malloc and free in the plugin API. This is the only
`synchronizeAsyncInfo` left in the omptarget layer.
Site note: On a V100 system the GridMini performance for small sizes
more than doubled.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D96379
The AsyncInfo should be passed everywhere and it should offer a way to
ensure synchronization, given a libomptarget Device.
This replaces D96431.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D96438
This unifies the API of `target` relative to `targetUpdateData` and
such.
Reviewed By: tianshilei1992, grokos
Differential Revision: https://reviews.llvm.org/D96429
The struct and enum alignments are kept by disabling clang-format for
that code region.
Reviewed By: tianshilei1992, JonChesterfield, grokos
Differential Revision: https://reviews.llvm.org/D96428
This silences warnings like these, in mingw builds with clang:
runtime/src/kmp_atomic.h:1021:13: warning: '__kmpc_atomic_cmplx8_rd' has C-linkage specified, but returns user-defined type 'kmp_cmplx64' (aka '__kmp_cmplx64_t') which is incompatible with C [-Wreturn-type-c-linkage]
runtime/src/z_Windows_NT_util.cpp:479:17: warning: cast from 'volatile void *' to 'type-parameter-0-0 *' drops volatile qualifier [-Wcast-qual]
flag = (C *)th->th.th_sleep_loc;
runtime/src/z_Windows_NT_util.cpp:1321:14: warning: cast to 'void *' from smaller integer type 'DWORD' (aka 'unsigned long') [-Wint-to-void-pointer-cast]
} else if ((void *)exit_val != (void *)th) {
Differential Revision: https://reviews.llvm.org/D96585
Add ifdefs around one function that only is used in unix build
configurations.
Add a void cast for a windows specific function that currently is
unused but may be intended to be used at some point.
Differential Revision: https://reviews.llvm.org/D96584
These variables are used only in certain build configurations,
or marked with a todo comment indicating that they should be
used/checked/reported.
Differential Revision: https://reviews.llvm.org/D96582
MinGW build configurations don't support this pragma (unless
compiling with clang, with -fms-extensions, and linking with
lld), and at least clang warns about it.
This library does end up linked by the cmake files anyway (as
long as the check works properly).
Differential Revision: https://reviews.llvm.org/D96581
check_library_exists fails for stdcall functions, because that
check doesn't include the necessary headers (and thus fails with
an undefined reference to _EnumProcessModules, when the import
library symbol actually is called _EnumProcessModules@16).
Merge the two previous checks check_include_files and
check_library_exists into one with check_c_source_compiles, and
merge the variables that indicate whether it succeeded.
Differential Revision: https://reviews.llvm.org/D96580
[libomptarget][amdgcn] Build amdgcn devicertl as openmp
Change cmake to build as openmp and fix up some minor errors in the code.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D96533
Three minor changes in this patch:
- added UNLIKELY hint to few rarely executed branches;
- replaced couple of run time checks with debug assertions;
- moved check of presence of ittnotify tool from inside the function call.
Differential Revision: https://reviews.llvm.org/D95816
This patch enables omp_get_num_devices() and omp_get_initial_device() on
Windows by providing an alternative to dlsym on Windows, and proposes to
add a new libomptarget entry, __tgt_get_num_devices().
Differential Revision: https://reviews.llvm.org/D96182
This patch adds lower-bound and upper-bound to num_teams clause
according to OpenMP 5.1 specification. The initial number of teams
created is implementation defined, but it will be greater than or
equal to lower-bound and less than or equal to upper-bound. If
num_teams clause is not specified, the number of teams created is
implementation defined, but it will be greater or equal to 1.
Differential Revision: https://reviews.llvm.org/D95820
[libomptarget][amdgcn] Tolerate deadstripped device_state variable
The device_state variable may have been deadstripped. Similar to
device_environment, leave detection of missing but used symbol to loader.
Reviewed By: pdhaliwal
Differential Revision: https://reviews.llvm.org/D96330
[libomptarget][amdgcn] Tolerate deadstripped env variable
Discovered by Pushpinder. If the device_environment variable is unused
it can be deadstripped, in which case we should not abort due to it
missing. This change is safe in that a missing symbol which is actually
used can be reported by both linker and loader, and a missing unused
symbol is better deadstripped than left in the image.
Reviewed By: pdhaliwal
Differential Revision: https://reviews.llvm.org/D96329
Currently if there is not kernel argument, device synchronization will
be skipped. This can lead to two issues:
1. If there is any device error, it will not be captured;
2. The target region might end before the kernel is done, which is not spec
conformant.
The test added in this patch only runs on NVPTX platform, although it will not
be executed by Phab at all. It also requires `not` which is not available on most
systems.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D96067
The header `assert.h` needs to be included in order to use `assert` in the code.
When building NVPTX `deviceRTLs` on a CUDA free system, it requires headers from
`gcc-multilib`, which some systems don't have. This patch drops the use of
`assert` in common parts of `deviceRTLs`. In light of
`openmp/libomptarget/deviceRTLs/amdgcn/src/target_impl.h`, a code block
```
if (!cond)
__builtin_trap();
```
is being used. The builtin will be translated to `call void @llvm.trap()`, and
the corresponding PTX is `trap;`.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D95986
New affinity patch introduced legitimate sign-compare warnings that
clang doesn't report but GCC-10 does. This removes the warnings by
changing two variables types to unsigned.
Differential Revision: https://reviews.llvm.org/D95818
From https://bugs.llvm.org/show_bug.cgi?id=48973, we know that
`std::call_once(PM->RTLs.initFlag, &RTLsTy::LoadRTLs, PM->RTLs)` causes compile
time problems in libstdc++v3 5.3.1. This is because there was a defect in the
standard regarding the `call_once` (LWG 2442). This was fixed in libstdc++ soon
thereafter, but there are likely other standard libraries where this will fail.
By matching this function call with the other one, we fix this bug.
Differential Revision: https://reviews.llvm.org/D95769
FileCheck is required for OpenMP tests. The current detection can fail
if building OpenMP in-tree when user sets `LLVM_INSTALL_TOOLCHAIN_ONLY=ON`. As a
result, CMake will raise an error and the compilation will be broken. This patch
fixed the issue. When `FileCheck` is not a target, tests will just be skipped.
Reviewed By: jdoerfert, JonChesterfield
Differential Revision: https://reviews.llvm.org/D95689
Summary:
One option for the LIBOMPTARGET_INFO environment variable is to print the current status of the device's data mappings. These are a shared resource among threads so this needs to be protected when using multiple streams.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95786
This patch refines the logic to choose compute capabilites via the
environment variable `LIBOMPTARGET_NVPTX_COMPUTE_CAPABILITIES`. It supports the
following values (all case insensitive):
- "all": Build `deviceRTLs` for all supported compute capabilites;
- "auto": Only build for the compute capability auto detected. Note that this
requires CUDA. If CUDA is not found, a CMake fatal error will be raised.
- "xx,yy" or "xx;yy": Build for compute capabilities `xx` and `yy`.
If `LIBOMPTARGET_NVPTX_COMPUTE_CAPABILITIES` is not set, it is equivalent to set
it to `all`.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95687
This patch introduces a new environment variable to force monotonic
behavior for users that absolutely need it. This is in anticipation
of 5.0 change that uses non-monotonic behavior for dynamic scheduling
by default. Fixes for that and the actual switch are coming soon.
Differential Revision: https://reviews.llvm.org/D95263
Added release note for new `deviceRTLs` and hidden helper task for LLVM
12.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95584
This patch created a new header file `target_interface.h` for declarations of all target dependent functions. All future targets can get things work by simply implementing all functions declared in the header and macros/data same as each `target_impl.h`.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D95300
In the past `-O1` was used when building NVPTX bitcode libraries. After
we switched to OpenMP, `-O1` was missing by mistake, leading to a huge performance
regression.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D95545
Alexey Bataev