If we decided to delete a mapping entry we did not act on it right away
but first issued and waited for memory copies. In the meantime some
other thread might reuse the entry. While there was some logic to avoid
colliding on the actual "deletion" part, there were two races happening:
1) The data transfer back of the thread deleting the entry and
the data transfer back of the thread taking over the entry raced.
2) The update to the shadow map happened regardless if the entry was
actually reused by another thread which left the shadow map in a
inconsistent state.
To fix both issues we will now update the shadow map and delete the
entry only if we are sure the thread is responsible for deletion, hence
no other thread took over the entry and reused it. We also wait for a
potential former data transfer from the device to finish before we issue
another one that would race with it.
Fixes https://github.com/llvm/llvm-project/issues/54216
Differential Revision: https://reviews.llvm.org/D121058
This patch solves two problems with the `HostDataToTargetMap` (HDTT
map) which caused races and crashes before:
1) Any access to the HDTT map needs to be exclusive access. This was not
the case for the "dump table" traversals that could collide with
updates by other threads. The new `Accessor` and `ProtectedObject`
wrappers will ensure we have a hard time introducing similar races in
the future. Note that we could allow multiple concurrent
read-accesses but that feature can be added to the `Accessor` API
later.
2) The elements of the HDTT map were `HostDataToTargetTy` objects which
meant that they could be copied/moved/deleted as the map was changed.
However, we sometimes kept pointers to these elements around after we
gave up the map lock which caused potential races again. The new
indirection through `HostDataToTargetMapKeyTy` will allows us to
modify the map while keeping the (interesting part of the) entries
valid. To offset potential cost we duplicate the ordering key of the
entry which avoids an additional indirect lookup.
We should replace more objects with "protected objects" as we go.
Differential Revision: https://reviews.llvm.org/D121057
There are two problems this patch tries to address:
1) We currently free resources in a random order wrt. plugin and
libomptarget destruction. This patch should ensure the CUDA plugin
is less fragile if something during the deinitialization goes wrong.
2) We need to support (hard) pause runtime calls eventually. This patch
allows us to free all associated resources, though we cannot
reinitialize the device yet.
Follow up patch will associate one event pool per device/context.
Differential Revision: https://reviews.llvm.org/D120089
This implements the runtime portion of the interop directive.
It expects the frontend and IRBuilder portions to be in place
for proper execution. It currently works only for GPUs
and has several TODOs that should be addressed going forward.
Reviewed By: RaviNarayanaswamy
Differential Revision: https://reviews.llvm.org/D106674
In the OpenMC app we saw `omp target update` spending an awful lot of
time in the shadow map traversal without ever doing any update there.
There are two cases that allow us to avoid the traversal completely.
The simplest thing is that small updates cannot (reasonably) contain
an attached pointer part. The other case requires to track in the
mapping table if an entry might contain an attached pointer as part.
Given that we have a single location shadow map entries are created,
the latter is actually fairly easy as well.
Differential Revision: https://reviews.llvm.org/D113124
Atomic handling of map clauses was introduced to comply with the OpenMP
standard (see D104418). However, many apps won't need this feature which
can be costly in certain situations. To allow for applications to
opt-out we now introduce the `LIBOMPTARGET_MAP_FORCE_ATOMIC` environment
flag that voids the atomicity guarantee of the standard for map clauses
again, shifting the burden to the user.
This patch also de-duplicates the code that introduces the events used
to enforce atomicity as a cleanup.
Differential Revision: https://reviews.llvm.org/D117627
The async data movement can cause data race if the target supports it.
Details can be found in [1]. This patch tries to fix this problem by attaching
an event to the entry of data mapping table. Here are the details.
For each issued data movement, a new event is generated and returned to `libomptarget`
by calling `createEvent`. The event will be attached to the corresponding mapping table
entry.
For each data mapping lookup, if there is no need for a data movement, the
attached event has to be inserted into the queue to gaurantee that all following
operations in the queue can only be executed if the event is fulfilled.
This design is to avoid synchronization on host side.
Note that we are using CUDA terminolofy here. Similar mechanism is assumped to
be supported by another targets. Even if the target doesn't support it, it can
be easily implemented in the following fall back way:
- `Event` can be any kind of flag that has at least two status, 0 and 1.
- `waitEvent` can directly busy loop if `Event` is still 0.
My local test shows that `bug49334.cpp` can pass.
Reference:
[1] https://bugs.llvm.org/show_bug.cgi?id=49940
Reviewed By: grokos, JonChesterfield, ye-luo
Differential Revision: https://reviews.llvm.org/D104418
This patch adds an external interface to access the dynamic shared
memory buffer in the device runtime. The function introduced is
``llvm_omp_get_dynamic_shared``. This includes a host-side
definition that only returns a null pointer so that it can be used when
host-fallback is enabled without crashing. Support for dynamic shared
memory was also ported to the old device runtime.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D110957
Follow on to D110006, related to D110957
Where implementations have diverged this resolves to match the new DeviceRTL
- replaces definitions of this struct in deviceRTL and plugins with include
- changes the dynamic_shared_size field from D110006 to 32 bits
- handles stdint being unavailable in DeviceRTL
- adds a zero initializer for the field to amdgpu
- moves the extern declaration for deviceRTL to target_interface
(omptarget.h is more natural, but doesn't work due to include order
with debug.h)
- Renames the fields everywhere to match the LLVM format used in DeviceRTL
- Makes debug_level uint32_t everywhere (previously sometimes int32_t)
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D111069
The defintion of OFFLOAD_SUCCESS and OFFLOAD_FAIL used in plugin APIs and libomptarget public APIs are not consistent.
Create __tgt_target_return_t for libomptarget public APIs.
Differential Revision: https://reviews.llvm.org/D109304
This patch implements OpenMP runtime support for an original OpenMP
extension we have developed to support OpenACC: the `ompx_hold` map
type modifier. The previous patch in this series, D106509, implements
Clang support and documents the new functionality in detail.
Reviewed By: grokos
Differential Revision: https://reviews.llvm.org/D106510
This patch adds the support form event related interfaces, which will be used
later to fix data race. See D104418 for more details.
Reviewed By: jdoerfert, ye-luo
Differential Revision: https://reviews.llvm.org/D108528
This patch introduces the `llvm-omp-device-info` tool, which uses the
omptarget library and interface to query the device info from all the
available devices as seen by OpenMP. This is inspired by PGI's `pgaccelinfo`
Since omptarget usually requires a description structure with executable
kernels, I split the initialization of the RTLs and Devices to be able to
initialize all possible devices and query each of them.
This revision relies on the patch that introduces the print device info.
A limitation is that the order in which the devices are initialized, and the
corresponding device ID is not necesarily the one seen by OpenMP.
The changes are as follows:
1. Separate the RTL initialization that was performed in `RegisterLib` to its own `initRTLonce` function
2. Create an `initAllRTLs` method that initializes all available RTLs at runtime
3. Created the `llvm-deviceinfo.cpp` tool that uses `omptarget` to query each device and prints its information.
Example Output:
```
Device (0):
print_device_info not implemented
Device (1):
print_device_info not implemented
Device (2):
print_device_info not implemented
Device (3):
print_device_info not implemented
Device (4):
CUDA Driver Version: 11000
CUDA Device Number: 0
Device Name: Quadro P1000
Global Memory Size: 4236312576 bytes
Number of Multiprocessors: 5
Concurrent Copy and Execution: Yes
Total Constant Memory: 65536 bytes
Max Shared Memory per Block: 49152 bytes
Registers per Block: 65536
Warp Size: 32 Threads
Maximum Threads per Block: 1024
Maximum Block Dimensions: 1024, 1024, 64
Maximum Grid Dimensions: 2147483647 x 65535 x 65535
Maximum Memory Pitch: 2147483647 bytes
Texture Alignment: 512 bytes
Clock Rate: 1480500 kHz
Execution Timeout: Yes
Integrated Device: No
Can Map Host Memory: Yes
Compute Mode: DEFAULT
Concurrent Kernels: Yes
ECC Enabled: No
Memory Clock Rate: 2505000 kHz
Memory Bus Width: 128 bits
L2 Cache Size: 1048576 bytes
Max Threads Per SMP: 2048
Async Engines: Yes (2)
Unified Addressing: Yes
Managed Memory: Yes
Concurrent Managed Memory: Yes
Preemption Supported: Yes
Cooperative Launch: Yes
Multi-Device Boars: No
Compute Capabilities: 61
```
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D106752
This patch introduces a function in the device's plugin to print the
device information. This patch relates to another patch that introduces
a CLI tool to obtain the device information from the omplibrary directly.
It is inspired by PGI's pgaccelinfo.
The modifications are as follows:
1. Introduce the optional `void __tgt_rtl_print_device_info(RTLdevID)` function into the RTL.
2. Introduce the `bool __tgt_print_device_info(devID)` function into `omptarget` interface. Returns false if the RTL is not implemented
3. Added `bool printDeviceInfo(RTLDevID)` to the `DeviceTy`
4. Implement the `__tgt_rtl_print_device_info` for CUDA. Added additional CUDA Runtime calls.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D106751
Revision of D102858. Raise dlwrap arity argument to template argument
so the correct value is given in the error message. E.g. '2 == 1' instead of
'2 == trait<>::nargs'.
Arity higher than it should be:
Before diff
```
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: error:
static_assert failed due to requirement '2 == trait<cudaError_enum (*)(unsigned int)>::nargs'
"Arity Error"
DLWRAP_INTERNAL(cuInit, 2);
^~~~~~~~~~~~~~~~~~~~~~~~~~
...
$/include/dlwrap.h:166:3: note: expanded from macro
'DLWRAP_COMMON'
static_assert(ARITY == trait<decltype(&SYMBOL)>::nargs, "Arity Error"); \
```
After diff
In file included from $/plugins/cuda/dynamic_cuda/cuda.cpp:16:
```
$/include/dlwrap.h:131:3: error: static_assert failed due to
requirement '2UL == 1UL' "Arity Error"
static_assert(Requested == Required, "Arity Error");
^ ~~~~~~~~~~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: in
instantiation of function template specialization 'dlwrap::verboseAssert<2UL, 1UL>' requested
here
DLWRAP_INTERNAL(cuInit, 2);
```
Arity lower than it should be:
Before diff
```
$/plugins/cuda/dynamic_cuda/cuda.cpp:131:10: error: no
matching function for call to 'dlwrap_cuInit'
return dlwrap_cuInit(X);
^~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: candidate
function not viable: requires 0 arguments, but 1 was provided
DLWRAP_INTERNAL(cuInit, 0);
```
After diff
In file included from $/plugins/cuda/dynamic_cuda/cuda.cpp:16:
```
$/include/dlwrap.h:131:3: error: static_assert failed due to
requirement '0UL == 1UL' "Arity Error"
static_assert(Requested == Required, "Arity Error");
^ ~~~~~~~~~~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: in
instantiation of function template specialization 'dlwrap::verboseAssert<0UL, 1UL>' requested
here
DLWRAP_INTERNAL(cuInit, 0);
```
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D106543
This patch adds an information flag that indicated when data is being copied to
and from the device. This will be helpful for finding redundant or unnecessary
data transfers in applications.
Reviewed By: jdoerfert, grokos
Differential Revision: https://reviews.llvm.org/D103927
[libomptarget] Improve dlwrap compile time error diagnostic
The dlwrap interface takes an explict arity, e.g. DLWRAP(cuAlloc, 2);
This probably can't be eliminated as it controls the argument list of an
external symbol, not an inline header function. If the arity given is too
big, the error from clang referring to the line is in the middle of
implementation details.
/usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:1277:7: error: static_assert failed
due to requirement '0UL < tuple_size<std::tuple<>>::value' "tuple index is in range"
static_assert(__i < tuple_size<tuple<>>::value,
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:1260:7: ...
/usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:1260:7: ...
/home/amd/llvm-project/openmp/libomptarget/include/dlwrap.h:93:27 ...
/home/amd/llvm-project/openmp/libomptarget/plugins/cuda/dynamic_cuda/cuda.cpp:34:1: note: in
instantiation of template class 'dlwrap::trait<cudaError_enum (*)(unsigned long *, unsigned
long)>::arg<2>' requested here
DLWRAP(cuMemAlloc, 3);
^
/home/amd/llvm-project/openmp/libomptarget/include/dlwrap.h:51:31: ...
/home/amd/llvm-project/openmp/libomptarget/include/dlwrap.h:166:3: ...
/home/amd/llvm-project/openmp/libomptarget/include/dlwrap.h:133:3: ...
/home/amd/llvm-project/openmp/libomptarget/include/dlwrap.h:186:37: ...
If the arity is too small, the diagnostic is better:
cuda/dynamic_cuda/cuda.cpp:34:1: error: too few
arguments to function call, expected 2, have 1
DLWRAP(cuMemAlloc, 1);
This patch changes the diagnostic to:
cuda/dynamic_cuda/cuda.cpp:34:1: error:
static_assert failed due to requirement '1 == trait<cudaError_enum (*)(unsigned long *, unsigned
long)>::nargs' "Arity Error"
DLWRAP(cuMemAlloc, 1);
or
cuda/dynamic_cuda/cuda.cpp:34:1: error:
static_assert failed due to requirement '3 == trait<cudaError_enum (*)(unsigned long *, unsigned
long)>::nargs' "Arity Error"
DLWRAP(cuMemAlloc, 3);
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D102858
Summary:
This patch improves the implementation of D100774 by replacing the global
variable introduced with a function that returns a reference to an internal
one. This removes the need to define the variable in every plugin that uses it.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D101102
Summary:
This patch adds a new runtime function __tgt_set_info_flag that allows the
user to set the information level at runtime without using the environment
variable. Using this will require an extern function, but will eventually be
added into an auxilliary library for OpenMP support functions.
This patch required moving the current InfoLevel to a global variable which must
be instantiated by each plugin.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D100774
Summary:
This patch adds a feature to print information whenever the host-device pointer
mapping table is changed by inserting or removing an entry. This introduces a
new bit field for LIBOMPTARGET_INFO at position 0x8.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D100600
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
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
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
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
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
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
In much of the libomptarget interface we have an ident_t object now, if
it is not null we can use it to improve the profile output. For now, we
simply use the ident_t "source information string" as generated by the
FE.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D95282
[libomptarget] Build cuda plugin without cuda installed locally
Compiles a new file, `plugins/cuda/dynamic_cuda/cuda.cpp`, to an object file that exposes the same symbols that the plugin presently uses from libcuda. The object file contains dlopen of libcuda and cached dlsym calls. Also provides a cuda.h containing the subset that is used.
This lets the cmake file choose between the system cuda and a dlopen shim, with no changes to rtl.cpp.
The corresponding change to amdgpu is postponed until after a refactor of the plugin to reduce the size of the hsa.h stub required
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95155
Summary:
Prior to D91261 the information checked the OMP_MAP_TARGET_PARAM flag, change this as it has been removed. The INFO macro was changed to accept a flag as input to make conditionally printing information easier.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95133
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
Summary:
Add support for passing source locations to libomptarget runtime functions using the ident_t struct present in the rest of the libomp API. This will allow the runtime system to give much more insightful error messages and debugging values.
Reviewers: jdoerfert grokos
Differential Revision: https://reviews.llvm.org/D87946
Summary:
This patch adds basic support for priting the source location and names for the mapped variables. This patch does not support names for custom mappers. This is based on D89802.
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D90172
Summary:
This patch adds support for passing in the original delcaration name in the source file to the libomptarget runtime. This will allow the runtime to provide more intelligent debugging messages. This patch takes the original expression parsed from the OpenMP map / update clause and provides a textual representation if it was explicitly mapped, otherwise it takes the name of the variable declaration as a fallback. The information in passed to the runtime in a global array of strings that matches the existing ident_t source location strings using ";name;filename;column;row;;"
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D89802
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
Summary:
This patch adds basic support for priting the source location and names for the
mapped variables. This patch does not support names for custom mappers. This is
based on D89802. The names information currently will be printed out only in
debug mode or using env LIBOMPTARGET_INFO during execution. But the information
is added when availible to the Device and Private data structures. To get the
information out the code must be built with debug symbols on using -g or
-Rpass=openmp-opt
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D90172
