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
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
The basic design is to create an outer-most parallel team. It is not a regular team because it is only created when the first hidden helper task is encountered, and is only responsible for the execution of hidden helper tasks. We first use `pthread_create` to create a new thread, let's call it the initial and also the main thread of the hidden helper team. This initial thread then initializes a new root, just like what RTL does in initialization. After that, it directly calls `__kmpc_fork_call`. It is like the initial thread encounters a parallel region. The wrapped function for this team is, for main thread, which is the initial thread that we create via `pthread_create` on Linux, waits on a condition variable. The condition variable can only be signaled when RTL is being destroyed. For other work threads, they just do nothing. The reason that main thread needs to wait there is, in current implementation, once the main thread finishes the wrapped function of this team, it starts to free the team which is not what we want.
Two environment variables, `LIBOMP_NUM_HIDDEN_HELPER_THREADS` and `LIBOMP_USE_HIDDEN_HELPER_TASK`, are also set to configure the number of threads and enable/disable this feature. By default, the number of hidden helper threads is 8.
Here are some open issues to be discussed:
1. The main thread goes to sleeping when the initialization is finished. As Andrey mentioned, we might need it to be awaken from time to time to do some stuffs. What kind of update/check should be put here?
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D77609
The basic design is to create an outer-most parallel team. It is not a regular team because it is only created when the first hidden helper task is encountered, and is only responsible for the execution of hidden helper tasks. We first use `pthread_create` to create a new thread, let's call it the initial and also the main thread of the hidden helper team. This initial thread then initializes a new root, just like what RTL does in initialization. After that, it directly calls `__kmpc_fork_call`. It is like the initial thread encounters a parallel region. The wrapped function for this team is, for main thread, which is the initial thread that we create via `pthread_create` on Linux, waits on a condition variable. The condition variable can only be signaled when RTL is being destroyed. For other work threads, they just do nothing. The reason that main thread needs to wait there is, in current implementation, once the main thread finishes the wrapped function of this team, it starts to free the team which is not what we want.
Two environment variables, `LIBOMP_NUM_HIDDEN_HELPER_THREADS` and `LIBOMP_USE_HIDDEN_HELPER_TASK`, are also set to configure the number of threads and enable/disable this feature. By default, the number of hidden helper threads is 8.
Here are some open issues to be discussed:
1. The main thread goes to sleeping when the initialization is finished. As Andrey mentioned, we might need it to be awaken from time to time to do some stuffs. What kind of update/check should be put here?
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D77609
This patch partially prepares the runtime source code to be built with
-Wconversion, which should trigger warnings if any implicit conversions
can possibly change a value. For builds done with icc or gcc, all such
warnings are handled in this patch. clang gives a much longer list of
warnings, particularly for sign conversions, which the other compilers
don't report. The -Wconversion flag is commented into cmake files, but
I'm not going to turn it on. If someone thinks it is important, and wants
to fix all the clang warnings, they are welcome to.
Types of changes made here involve either improving the consistency of types
used so that no conversion is needed, or else performing careful explicit
conversions, when we're sure a problem won't arise.
Patch is a combination of changes by Terry Wilmarth and Johnny Peyton.
Differential Revision: https://reviews.llvm.org/D92942
This patch adds new API __kmpc_taskloop_5 to accomadate strict
modifier (introduced in OpenMP 5.1) in num_tasks and grainsize
clause.
Differential Revision: https://reviews.llvm.org/D92352
These changes add support for Intel's umonitor/umwait usage in wait
code, for architectures that support those intrinsic functions. Usage of
umonitor/umwait is off by default, but can be turned on by setting the
KMP_USER_LEVEL_MWAIT environment variable.
Differential Revision: https://reviews.llvm.org/D91189
Added UNLIKELY hint to one-time or rarely executed branches.
This improves performance of the library on some tasking benchmarks.
Differential Revision: https://reviews.llvm.org/D92322
Once __kmp_task_finish is not executed for proxy tasks,
move mutexinoutset dependency code to __kmp_release_deps
which is executed for all task kinds.
Differential Revision: https://reviews.llvm.org/D92326
Add check of negative gtid before indexing __kmp_threads.
This makes static analyzers happier.
This is the first part of the patch split in two parts.
Differential Revision: https://reviews.llvm.org/D84062
The OpenMP spec has the task-fulfill event for a call to omp_fulfill_event.
If the task did not yet finish execution, ompt_task_early_fulfill is used,
otherwise ompt_task_late_fulfill.
If a task does not complete, when the execution finishes (i.e., the task goes
in detached mode), ompt_task_detach instead of ompt_task_complete must be
used, when the next task is scheduled.
A test for both cases is included, which only work with clang-11+
Reviewed By: hbae
Differential revision: https://reviews.llvm.org/D80843
__kmp_realloc_task_deque implicitly assumes, that the task queue is full
(ntasks == size), therefore tail = size in line 319.
An assertion is added to document this assumption.
The first check for a full queue is before the locking and might not hold
when the lock is taken. So, we need to check again for this condition when
we have the lock.
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D80480
Spurious assertion failures are symptoms of a race condition for the handling
of detached tasks:
Assertion failure at kmp_tasking.cpp(3744): taskdata->td_flags.complete == 1.
Assertion failure at kmp_tasking.cpp(710): taskdata->td_flags.executing == 0.
in the case of detach=true, all accesses to taskdata in __kmp_task_finish need
to happen before (~line 873):
taskdata->td_flags.proxy = TASK_PROXY;
This assignment signals to __kmp_fulfill_event, that the task will need to be
freed there. So, conceptionally the ownership of taskdata is moved.
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D79702
Remove all older OMP spec versioning from the runtime and build system.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D64534
llvm-svn: 365963
Implemented task modifier in two versions - one without taking into account
omp_orig variable (the omp_orig still can be processed by compiler without help
of the library, but each reduction object will need separate initializer with
global access to omp_orig), another with omp_orig variable included into
interface (single initializer can be used for multiple reduction objects of
the same type). Second version can be used when the omp_orig is not globally
accessible, or to optimize code in case of multiple reduction objects
of the same type.
Patch by Andrey Churbanov
Differential Revision: https://reviews.llvm.org/D60976
llvm-svn: 359710
This patch cleans up the yielding code and makes it optional. An
environment variable, KMP_USE_YIELD, was added. Yielding is still
on by default (KMP_USE_YIELD=1), but can be turned off completely
(KMP_USE_YIELD=0), or turned on only when oversubscription is detected
(KMP_USE_YIELD=2). Note that oversubscription cannot always be detected
by the runtime (for example, when the runtime is initialized and the
process forks, oversubscription cannot be detected currently over
multiple instances of the runtime).
Because yielding can be controlled by user now, the library mode
settings (from KMP_LIBRARY) for throughput and turnaround have been
adjusted by altering blocktime, unless that was also explicitly set.
In the original code, there were a number of places where a double yield
might have been done under oversubscription. This version checks
oversubscription and if that's not going to yield, then it does
the spin check.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D58148
llvm-svn: 355120
The three switch fallthrough generate a warning with -Wimplicit-fallthrough.
Two are documented as fallthrough, one is not, but I think the intention is to also fallthrough in kmp_tasking.cpp.
Not sure whether kmp.h is the best place to define the macro.
Reviewers: jlpeyton, AndreyChurbanov, Hahnfeld
Reviewed By: jlpeyton
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D56397
llvm-svn: 353052
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
Add omp_pause_resource and omp_pause_resource_all API and enum, plus stub for
internal implementation. Implemented callable helper function to do local pause,
and added basic functionality for hard and soft pause.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D55078
llvm-svn: 351372
This patch updates the implementation of the ompt_frame_t, ompt_wait_id_t
and ompt_state_t. The final version of the OpenMP 5.0 spec added the "t"
for these types.
Furthermore the structure for ompt_frame_t changed and allows to specify
that the reenter frame belongs to the runtime.
Patch partially prepared by Simon Convent
Reviewers: hbae
llvm-svn: 349458
Summary:
I have discovered this because i wanted to experiment with
building static libomp (with openmp-4.0 support only)
for debugging purposes.
There are three kinds of problems here:
1. `__kmp_compare_and_store_acq()` simply does not exist.
It was added in D47903 by @jlpeyton.
I'm guessing `__kmp_atomic_compare_store_acq()` was meant.
2. In `__kmp_is_ticket_lock_initialized()`,
`lck->lk.initialized` is `std::atomic<bool>`,
while `lck` is `kmp_ticket_lock_t *`.
Naturally, they can't be equality-compared.
Either, it should return the value read from `lck->lk.initialized`,
or do what `__kmp_is_queuing_lock_initialized()` does,
compare the passed pointer with the field in the struct
pointed by the pointer. I think the latter is correct-er choice here.
3. Tests were not versioned.
They assume that `LIBOMP_OMP_VERSION` is at the latest version.
This does not touch LIBOMP_OMP_VERSION=30. That is still broken.
Reviewers: jlpeyton, Hahnfeld, AndreyChurbanov
Reviewed By: AndreyChurbanov
Subscribers: guansong, jfb, openmp-commits, jlpeyton
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D55496
llvm-svn: 349260
This patch adds __kmpc_omp_reg_task_with_affinity to register affinity
information for tasks. For now, the affinity information is not used,
and the function always succeeds. This also adds the kmp_task_affinity_info_t
structure to store the task affinity information.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D55026
llvm-svn: 347907
This patch puts the __kmpc_critical_with_hint function in dllexports
and also replaces some OMP_45_ENABLED to OMP_50_ENABLED
Differential Revision: https://reviews.llvm.org/D52380
llvm-svn: 343143
This change improves the performance of 376.kdtree by giving the compiler an
opportunity to do inlining and other optimizations for the call path,
__kmpc_omp_task_complete_if0()->__kmp_task_finish(), which is one of the hot
paths in the program; some functions in kmp_taskdeps.cpp were moved to the new
header file, kmp_taskdeps.h to achieve this.
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D51889
llvm-svn: 343138
Some types and callback signatures have changed from TR6 to TR7.
Major changes (only adding signatures and stubs):
(-remove idle callback) done by D48362
-add reduction and dispatch callback
-add get_task_memory and finalize_tool runtime entry points
-ompt_invoker_t becomes ompt_parallel_flag_t
-more types of sync_regions
Patch provided by Simon Convent
Reviewers: hbae, protze.joachim
Differential Revision: https://reviews.llvm.org/D50774
llvm-svn: 341834
The __kmp_execute_tasks_template() function reads the task_team and
current_task from the thread structure. There appears to be a pathological
timing where the number of threads in the hot team decreases and so a
thread is put in the pool via __kmp_free_thread(). It could be the case that:
1) A thread reads th_task_team into task_team local variables
and is then interrupted by the OS
2) Master frees the thread and sets current task and task team to NULL
3) The thread reads current_task as NULL
When this happens, current_task is dereferenced and a segfault occurs.
This patch just checks for current_task to not be NULL as well.
Differential Revision: https://reviews.llvm.org/D50651
llvm-svn: 340632
Exclude nested explicit tasks from timing, only outer level explicit task
counted and its time added to barrier arrive time for the thread.
Differential Revision: https://reviews.llvm.org/D50584
llvm-svn: 340628
This patch cleans up unused functions, variables, sign compare issues, and
addresses some -Warning flags which are now enabled including -Wcast-qual.
Not all the warning flags in LibompHandleFlags.cmake are enabled, but some
are with this patch.
Some __kmp_gtid_from_* macros in kmp.h are switched to static inline functions
which allows us to remove the awkward definition of KMP_DEBUG_ASSERT() and
KMP_ASSERT() macros which used the comma operator. This had to be done for the
innumerable -Wunused-value warnings related to KMP_DEBUG_ASSERT()
Differential Revision: https://reviews.llvm.org/D49105
llvm-svn: 339393
From the bug report, the runtime needs to initialize the nproc variables
(inside middle init) for each root when the task is encountered, otherwise,
a segfault can occur.
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=36720
Differential Revision: https://reviews.llvm.org/D49996
llvm-svn: 338313
Summary:
When OMPT is not supported the __kmp_omp_task() function is passed the parameters in the wrong order. This is a fix related to patch D47709.
Reviewers: Hahnfeld, sconvent, caomhin, jlpeyton
Reviewed By: Hahnfeld
Subscribers: guansong, openmp-commits
Differential Revision: https://reviews.llvm.org/D50001
llvm-svn: 338295
Fix the order of callbacks related to the taskloop construct.
Add the iteration_count to work callbacks (according to the spec).
Use kmpc_omp_task() instead of kmp_omp_task() to include OMPT callbacks.
Add a testcase.
Patch by Simon Convent
Reviewed by: protze.joachim, hbae
Subscribers: openmp-commits
Differential Revision: https://reviews.llvm.org/D47709
llvm-svn: 338146
