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
Summary:
This patch adds more fine-grained support over which information is output from the libomptarget runtime when run with the environment variable LIBOMPTARGET_INFO set. An extensible set of flags can be used to pick and choose which information the user is interested in.
Reviewers: jdoerfert JonChesterfield grokos
Differential Revision: https://reviews.llvm.org/D93727
This patch is the runtime support for https://reviews.llvm.org/D84192.
In order not to modify the tgt_target_data_update information but still be
able to pass the extra information for non-contiguous map item (offset,
count, and stride for each dimension), this patch overload arg when
the maptype is set as OMP_TGT_MAPTYPE_DESCRIPTOR. The origin arg is for
passing the pointer information, however, the overloaded arg is an
array of descriptor_dim:
```
struct descriptor_dim {
int64_t offset;
int64_t count;
int64_t stride
};
```
and the array size is the dimension size. In addition, since we
have count and stride information in descriptor_dim, we can replace/overload the
arg_size parameter by using dimension size.
Reviewed By: grokos, tianshilei1992
Differential Revision: https://reviews.llvm.org/D82245
This patch is the runtime support for https://reviews.llvm.org/D84192.
In order not to modify the tgt_target_data_update information but still be
able to pass the extra information for non-contiguous map item (offset,
count, and stride for each dimension), this patch overload arg when
the maptype is set as OMP_TGT_MAPTYPE_DESCRIPTOR. The origin arg is for
passing the pointer information, however, the overloaded arg is an
array of descriptor_dim:
```
struct descriptor_dim {
int64_t offset;
int64_t count;
int64_t stride
};
```
and the array size is the dimension size. In addition, since we
have count and stride information in descriptor_dim, we can replace/overload the
arg_size parameter by using dimension size.
Reviewed By: grokos
Differential Revision: https://reviews.llvm.org/D82245
There is a non-conforming use of variable-sized array in the test case `parallel_offloading_map.c`. This patch fixed it.
Reviewed By: protze.joachim
Differential Revision: https://reviews.llvm.org/D90642
The implementation of target nowait just wraps the target region into a task. The essential four parameters (base ptr, ptr, size, mapper) are taken as firstprivate such that they will be copied to the private location. When there is no user-defined mapper, the mapper variable will be nullptr. However, it will be still copied to the corresponding place. Therefore, a memcpy will be generated and the source pointer will be nullptr, causing a segmentation fault. The root cause is when calling `emitOffloadingArraysArgument`, the last argument `Options` has a field about whether it requires a task. It only takes depend clause into account. In this patch, the nowait clause is also included.
There're two things that will be done in another patches:
1. target data nowait has not been supported yet. D90099 added the support.
2. When there is no mapper, the mapper array can be nullptr no matter whether it requires outer task or not. It can avoid an unnecessary data copy. This is an optimization that is covered in D90101.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D89844
Summary:
This patch starts adding support for adding information dumps to libomptarget
and rtl plugins. The information printing is controlled by the
LIBOMPTARGET_INFO environment variable introduced in D86483. The goal of this
patch is to provide the user with additional information about the device
during kernel execution and providing the user with information dumps in the
case of failure. This patch added the ability to dump the pointer mapping table
as well as printing the number of blocks and threads in the cuda RTL.
Reviewers: jdoerfort gkistanova ye-luo
Subscribers: guansong openmp-commits sstefan1 yaxunl ye-luo
Tags: #OpenMP
Differential Revision: https://reviews.llvm.org/D87165
Target memory manager is introduced in this patch which aims to manage target
memory such that they will not be freed immediately when they are not used
because the overhead of memory allocation and free is very large. For CUDA
device, cuMemFree even blocks the context switch on device which affects
concurrent kernel execution.
The memory manager can be taken as a memory pool. It divides the pool into
multiple buckets according to the size such that memory allocation/free
distributed to different buckets will not affect each other.
In this version, we use the exact-equality policy to find a free buffer. This
is an open question: will best-fit work better here? IMO, best-fit is not good
for target memory management because computation on GPU usually requires GBs of
data. Best-fit might lead to a serious waste. For example, there is a free
buffer of size 1960MB, and now we need a buffer of size 1200MB. If best-fit,
the free buffer will be returned, leading to a 760MB waste.
The allocation will happen when there is no free memory left, and the memory
free on device will take place in the following two cases:
1. The program ends. Obviously. However, there is a little problem that plugin
library is destroyed before the memory manager is destroyed, leading to a fact
that the call to target plugin will not succeed.
2. Device is out of memory when we request a new memory. The manager will walk
through all free buffers from the bucket with largest base size, pick up one
buffer, free it, and try to allocate immediately. If it succeeds, it will
return right away rather than freeing all buffers in free list.
Update:
A threshold (8KB by default) is set such that users could control what size of memory
will be managed by the manager. It can also be configured by an environment variable
`LIBOMPTARGET_MEMORY_MANAGER_THRESHOLD`.
Reviewed By: jdoerfert, ye-luo, JonChesterfield
Differential Revision: https://reviews.llvm.org/D81054
Summary:
In current implementation, D2D memcpy is first to copy data back to host and then
copy from host to device. This is very efficient if the device supports D2D
memcpy, like CUDA.
In this patch, D2D memcpy will first try to use native supported driver API. If
it fails, fall back to original way. It is worth noting that D2D memcpy in this
scenerio contains two ideas:
- Same devices: this is the D2D memcpy in the CUDA context.
- Different devices: this is the PeerToPeer memcpy in the CUDA context.
My implementation merges this two parts. It chooses the best API according to
the source device and destination device.
Reviewers: jdoerfert, AndreyChurbanov, grokos
Reviewed By: jdoerfert
Subscribers: yaxunl, guansong, sstefan1, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D80649
Summary:
Instead of using global variables with unpredicted time of
deinitialization, use dynamically allocated variables with functions
explicitly marked as global constructor/destructor and priority. This
allows to prevent the crash because of the incorrect order of dynamic
libraries deinitialization.
Reviewers: grokos, hfinkel
Subscribers: caomhin, kkwli0, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D74837
Summary:
If the dynamically loaded module has been compiled with -fopenmp-targets
and has no target regions, it has empty target descriptor. It leads to a
crash at the runtime if another module has at least one target region
and at least one entry in its descriptor. The runtime library is unable
to load the empty binary descriptor and terminates the execution.
Caused by a clang-offload-wrapper.
Reviewers: grokos, jdoerfert
Subscribers: caomhin, kkwli0, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D72472
Summary:
This patch adds support for using unified memory in the case of regular maps that happen when a target region is offloaded to the device.
For cases where only a single version of the data is required then the host address can be used. When variables need to be privatized in any way or globalized, then the copy to the device is still required for correctness.
Reviewers: ABataev, jdoerfert, Hahnfeld, AlexEichenberger, caomhin, grokos
Reviewed By: Hahnfeld
Subscribers: mgorny, guansong, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D65001
llvm-svn: 368192
Remove loopTripCnt from threaded device stack after consuming it.
Added a libomptarget DP message to aid in future debugging and to
validate the added testcase, which only runs in Debug build.
Differential Revision: https://reviews.llvm.org/D64808
llvm-svn: 366349
Summary:
We used to call __kmpc_omp_taskwait function with global threadid set to
0. It may crash the application at the runtime if the thread executing
target region is not a master thread.
Reviewers: grokos, kkwli0
Subscribers: guansong, jdoerfert, caomhin, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D64571
llvm-svn: 366220
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
This adds AArch64 support to recently added part of the runtime responsible for offloading to target. This piece of code allows offloading-to-self on AArch64 machines.
Differential Revision: https://reviews.llvm.org/D30644
llvm-svn: 297070
