These entry points are never called by Clang trunk nor clang-ykt. If
XL doesn't use them either, they can finally go away.
Differential Revision: https://reviews.llvm.org/D52700
llvm-svn: 365817
Summary:
__kmpc_push_tripcount function is not thread safe and may lead to data
race when the target regions are executed in parallel threads. The patch
makes loopTripCnt counter thread aware and stores the tripcount value
per thread in the map. Access to map is guarded by mutex to prevent
data race in the map itself.
Test is for NVPTX target because it does not work correctly on the
host. Seems to me, there is a problem in libomp with target regions in
the parallel threads.
Reviewers: grokos
Subscribers: guansong, jfb, jdoerfert, openmp-commits, kkwli0, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D64080
llvm-svn: 365332
Summary:
According to the OpenMP standard, flush makes a thread’s temporary view of memory consistent with memory and enforces an order on the memory operations of the variables explicitly specified or implied.
According to the Cuda toolkit documentation (https://docs.nvidia.com/cuda/archive/8.0/cuda-c-programming-guide/index.html#memory-fence-functions), __threadfence() functions provides required functionality.
__threadfence_system() also provides required functionality, but it also
includes some extra functionality, like synchronization of page-locked
host memory, synchronization for the host, etc. It is not required per
the standard and we can use more relaxed version of memory fence
operation.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jfb, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D62397
llvm-svn: 364572
Summary:
This patch adds support for handling variables under the:
```
#pragma omp declare target to()
```
clause when the
```
#pragma omp requires unified_shared_memory
```
is used.
The address of the host variable is copied into the device pointer just like for the declare target link case.
Reviewers: ABataev, caomhin, grokos, AlexEichenberger
Reviewed By: grokos
Subscribers: jcownie, guansong, jdoerfert, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D63106
llvm-svn: 363825
Summary:
The problems with __syncthreads() were fixed in clang >= 9.0 and the
original __syncthreads() can be used instead of the ptx instruction.
Reviewers: grokos
Subscribers: guansong, jdoerfert, openmp-commits, kkwli0, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D63515
llvm-svn: 363807
Summary: This patch enables the usage of a host variable on the device for declare target link variables when unified memory is available.
Reviewers: ABataev, caomhin, grokos
Reviewed By: grokos
Subscribers: Hahnfeld, guansong, jdoerfert, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D60884
llvm-svn: 362505
Summary:
Parallel level counter should be volatile to prevent some dangerous
optimiations by the ptxas. Otherwise, ptxas optimizations lead to
undefined behaviour in some cases.
Also, use __threadfence() for #pragma omp flush and if the barrier
should not be used (we have only one thread in the team), still perform
flush operation since the standard requires implicit flush when
executing barriers.
Reviewers: gtbercea, kkwli0, grokos
Subscribers: guansong, jfb, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D62199
llvm-svn: 361421
Summary:
Target link variables are currently implemented by creating a copy of the variables on the device side and unified memory never gets exploited.
When the prgram uses the:
```
#pragma omp requires unified_shared_memory
```
directive in conjunction with a declare target link, the linked variable is no longer allocated on the device and the host version is used instead.
This behavior is overridden by performing an explicit mapping.
A Clang side patch is required.
Reviewers: ABataev, AlexEichenberger, grokos, Hahnfeld
Reviewed By: AlexEichenberger, grokos, Hahnfeld
Subscribers: Hahnfeld, jfb, guansong, jdoerfert, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D60223
llvm-svn: 361294
Summary:
Patch improves performance of the full runtime mode by moving
threads limit counter to the shared memory. It also allows to save
global memory.
Reviewers: grokos, kkwli0, gtbercea
Subscribers: guansong, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61801
llvm-svn: 360584
Summary:
Patch improves performance of the full runtime mode by moving
number-of-threads counter to the shared memory. It also allows to save
global memory.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jfb, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61785
llvm-svn: 360457
Summary:
Patch improves performance of the full runtime mode by moving
thread-limit counter to the shared memory. It also allows to save
global memory.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jdoerfert, caomhin, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61526
llvm-svn: 359922
Summary:
Used parallelLevel[] counter to simplify and improve implementation of
the existing standard OpenMP functions. Functions are tested already in
several tests, the patch is NFC.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jdoerfert, caomhin, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61459
llvm-svn: 359892
Summary:
Previously for the different purposes we need to get the active/common
parallel level and with full runtime we iterated over all the records to
calculate this level. Instead, we can used the warp-based parallel level
counters used in no-runtime mode.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jfb, jdoerfert, caomhin, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61395
llvm-svn: 359822
Summary:
Function omp_get_thread_limit() in SPMD mode can return the maximum
available number of threads as a result.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D61378
llvm-svn: 359790
Summary:
The parallelLevel counter must be on per-thread basis to fully support
L2+ parallelism, otherwise we may end up with undefined behavior.
Introduce the parallelLevel on per-warp basis using shared memory. It
allows to avoid the problems with the synchronization and allows fully
support L2+ parallelism in SPMD mode with no runtime.
Reviewers: gtbercea, grokos
Subscribers: guansong, jdoerfert, caomhin, kkwli0, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D60918
llvm-svn: 359341
Fix the test to run it really in SPMD mode without runtime. Previously
it was run in SPMD + full runtime mode and does not allow to cehck the
functionality correctly.
llvm-svn: 358902
Summary:
If the kernel is executed in SPMD mode and the L2+ parallel for region
with the dynamic scheduling is executed, dynamic scheduling functions
are called. They expect full runtime support, but SPMD kernels may be
executed without the full runtime. It leads to the runtime crash of the
compiled program. Patch fixes this problem + fixes handling of the
parallelism level in SPMD mode, which is required as part of this patch.
Reviewers: gtbercea, kkwli0, grokos
Subscribers: guansong, jdoerfert, openmp-commits, caomhin
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D60578
llvm-svn: 358442
At the moment, support for runtime debug output using the
OMPTARGET_DEBUG=1 environment variable is only available with
CMAKE_BUILD_TYPE=Debug builds. The patch allows setting it independently
using the LIBOMPTARGET_ENABLE_DEBUG option, which is enabled by default
depending on CMAKE_BUILD_TYPE. That is, unless this option is set
explicitly, nothing changes. This is the same mechanism used by LLVM for
LLVM_ENABLE_ASSERTIONS.
This patch also removes adding -g -O0 in debug builds, it should be
handled by cmake's CMAKE_{C|CXX}_FLAGS_DEBUG configuration option.
Idea by Hal Finkel
Differential Revision: https://reviews.llvm.org/D55952
llvm-svn: 356998
Summary:
This patch adds a more sophisticated team reduction scheme to the OpenMP libomptarget-nvptx runtime.
The scheme uses a fixed size global memory buffer whose length can be adjusted via compiler flag:
```
-fopenmp-cuda-teams-reduction-recs-num=1024
```
The global buffer is a structure of arrays (with default size of 1024 each and controlled by the above flag), one array for each reduction variable.
Values in the buffer are processed by the last team to finish executing the body of the target region.
In addition to adding support for the new flag, the compiler also emits special functions used for the reduction of the intermediate reduction values. These changes will be added in a separate compiler patch following this one.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: guansong, jfb, jdoerfert, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D58409
llvm-svn: 354471
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351648
Summary: Replace existing infrastructure for tracking parallel level using global memory with a per-team shared memory variable. This minimizes the impact of the overhead of tracking the parallel level for non-nested cases.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: guansong, openmp-commits
Differential Revision: https://reviews.llvm.org/D55773
llvm-svn: 350747
Summary:
Previous implementation may cause the runtime crash when the number of
teams is > 1024. Patch fixes this problem + reduces number of the atomic
operations by 32 times.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jfb, openmp-commits, caomhin
Differential Revision: https://reviews.llvm.org/D56332
llvm-svn: 350524
Summary:
Reduced number of the used register + improved performance propagating
the information about current execution/data sharing mode directly from
the compiler, where it is possible.
In some cases, it requires new/reworked interfaces of the runtime
external functions. Old functions are marked as deprecated.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, jfb, openmp-commits, caomhin
Differential Revision: https://reviews.llvm.org/D56278
llvm-svn: 350405
The OpenMP runtime's cmake scripts do not correctly locate the
libdevice that the Debian/Ubuntu package nvidia-cuda-toolkit currently
includes, at least on my Ubuntu 18.04.1 installation. This patch
fixes that for me.
This problem was discussed at length in D55269. D40453 added a
similar adjustment in clang, but reviewers of D55269 concluded that,
for the OpenMP runtime, the right place to address this problem is in
cmake's CUDA support. However, it was also suggested we could add a
workaround to OpenMP's cmake scripts now. This patch contains such a
workaround, which I've tried to design so that it will have no harmful
effect if cmake improves in the future.
nvidia-cuda-toolkit also needs improvements because its intended
monolithic CUDA tree shim, /usr/lib/cuda, has many empty directories,
such as bin. I reported that at:
<https://bugs.launchpad.net/ubuntu/+source/nvidia-cuda-toolkit/+bug/1808999>
Reviewed By: grokos
Differential Revision: https://reviews.llvm.org/D55588
llvm-svn: 350377
Add omp_get_device_num() function for 5.0 which returns the number of the
device the current thread is running on. Currently, we are leaving it to the
compiler to handle this properly if it is called inside target.
Also, did some cleanup and updating of duplicate device API functions (in both
libomp and libomptarget) to make them into weak functions that check for the
symbol from libomptarget, and will call the version in libomptarget if it is
present. If any additional device API functions are implemented also in
libomptarget in the future, we should add the dlsym calls to the host functions.
Also, if the omp_target_* functions are to be implemented for the host (this has
been requested), they should attempt to call the libomptarget versions as well.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D55578
llvm-svn: 350352
Summary:
One of the LLVM optimizations, split critical edges, also clones tail
instructions. This is a dangerous operation for __syncthreads()
functions and this transformation leads to undefined behavior or
incorrect results. Patch fixes this problem by replacing __syncthreads()
function with the assembler instruction, which cost is too high and
wich cannot be copied.
Reviewers: grokos, gtbercea, kkwli0
Subscribers: guansong, openmp-commits, caomhin
Differential Revision: https://reviews.llvm.org/D56274
llvm-svn: 350333
Summary:
Avoid using of the atomic loop to wait for the completion of the
data-sharing interface initialization, use __shfl_sync instead for the
communication within the warp to signal other threads in the warp about
completion of the initialization.
Reviewers: gtbercea, kkwli0, grokos
Subscribers: guansong, jfb, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D56100
llvm-svn: 350129
Summary:
At high optimization level asserts lead to some unexpected results
because of auto-inserted unreachable instructions. This outlining
prevents some of such dangerous optimizations and leads to better
stability.
Reviewers: gtbercea, kkwli0, grokos
Subscribers: guansong, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D56101
llvm-svn: 350128
Summary:
Use the original shuffle implementation for __kmpc_shuffle_int64 since
default implementation uses the same implementation.
Reviewers: gtbercea
Subscribers: guansong, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D55514
llvm-svn: 348772
Summary:
Shuffle on 64bit data is allowed only for CUDA >= 9.0. Also, fixed the
constant for the mask, need one extra L in the end.
Reviewers: gtbercea, kkwli0
Subscribers: guansong, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D55440
llvm-svn: 348758
Summary:
Introduced special noinline function log that allows to save some
registers for optimized builds but with enabled logging. Also, it
increases the stability of the optimized builds with inlined runtime.
Reviewers: gtbercea, kkwli0
Reviewed By: gtbercea
Subscribers: caomhin, guansong, openmp-commits
Differential Revision: https://reviews.llvm.org/D55436
llvm-svn: 348606
Summary:
According to the standard, after memory flushing the changes in the
memory must be visible to all the threads in all teams. Patch fixes
this.
Reviewers: gtbercea, kkwli0
Subscribers: guansong, jfb, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D55370
llvm-svn: 348491
Summary:
Reworked runtime to make it compatible with the requirements of the
original runtime library. Also, simplified some code to reduce number of
function calls.
Reviewers: gtbercea, kkwli0
Subscribers: guansong, jfb, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D55130
llvm-svn: 348003
Summary: To enable the compiler to optimize parts of the function that are not needed when runtime can be omitted, a new version of the SPMD deinit kernel function is needed. This function takes the runtime required flag as an argument.
Reviewers: ABataev, kkwli0, caomhin
Reviewed By: ABataev
Subscribers: guansong, openmp-commits
Differential Revision: https://reviews.llvm.org/D54969
llvm-svn: 347714
Summary:
Added functions __kmpc_nvptx_teams_reduce_nowait_simple and
__kmpc_nvptx_teams_end_reduce_nowait_simple to implement basic support
for reductions across the teams.
Reviewers: gtbercea, kkwli0
Subscribers: guansong, jfb, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D54967
llvm-svn: 347710
Summary: Refactor the checking for SPMD mode and whether the runtime is initialized or not. This uses constant flags which enables the runtime to optimize out unused sections of code that depend on these flags.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: guansong, jfb, openmp-commits
Differential Revision: https://reviews.llvm.org/D54960
llvm-svn: 347698
Summary:
The base pointer for the lambda mapping must point to the lambda capture
placement and pointer must point to the captured variable itself. Patch
fixes this problem.
Reviewers: gtbercea
Subscribers: guansong, openmp-commits, kkwli0, caomhin
Differential Revision: https://reviews.llvm.org/D54260
llvm-svn: 346407
Summary:
The previously used combination `PTR_AND_OBJ | PRIVATE` could be used
for mapping of some data in Fortran. Changed it to `PTR_AND_OBJ |
LITERAL`.
Reviewers: gtbercea
Subscribers: guansong, caomhin, openmp-commits
Differential Revision: https://reviews.llvm.org/D54035
llvm-svn: 345981
Summary:
Current globalization scheme works correctly only for SPMD+lightweight
runtime mode and does not work for full runtime. Patch improves support
for the globalization scheme + reduces global memory consumption in
lightweight runtime mode.
Patch adds runtime functions to work with the statically allocated
global memory. It allows to improve performance and memory consumption.
This global memory must be allocated by the compiler.
Reviewers: grokos, kkwli0, gtbercea, caomhin
Subscribers: guansong, jfb, openmp-commits
Differential Revision: https://reviews.llvm.org/D53943
llvm-svn: 345976
Summary: In the case of coalesced global records, we need to push the exact data size passed in. This patch fixes this by outlining the common functionality of the previous push function and by adding a separate entry point for coalesced pushes. The pop function remains unchanged.
Reviewers: ABataev, grokos, caomhin
Reviewed By: ABataev, grokos
Subscribers: jholewinski, cfe-commits, Hahnfeld, guansong, jfb, openmp-commits
Differential Revision: https://reviews.llvm.org/D53141
llvm-svn: 345867
Jonas Hahnfeld