r179397 added Parallel.h and implemented it terms of concrt in 2013.
In 2015, a cross-platform implementation of the functions has appeared
and is in use everywhere but on Windows (r232419). r246219 hints that
<thread> had issues in MSVC2013, but r296906 suggests they've been fixed
now that we require 2015+.
So remove the concrt code. It's less code, and it sounds like concrt has
conceptual and performance issues, see PR41198.
I built blink_core.dll in a debug component build with full symbols and
in a release component build without any symbols. I couldn't measure a
performance difference for linking blink_core.dll before and after this
patch.
Differential Revision: https://reviews.llvm.org/D68820
llvm-svn: 374421
Summary:
Concurrent (e.g. nested) llvm::parallel::for_each() may lead to dead
locks. See PR35788 (fixed by rLLD322041) and PR41508 (fixed by D60757).
When parallel_for_each() is about to return, in ~Latch() called by
~TaskGroup(), a thread (in the default executor) may block in
Latch::sync() waiting for Count to become zero. If all threads in the
default executor are blocked, it is a dead lock.
To fix this, force serial execution if the current TaskGroup is not the
first one. For a nested llvm::parallel::for_each(), this parallelizes
the outermost loop and serializes inner loops.
Differential Revision: https://reviews.llvm.org/D61115
llvm-svn: 359182
to reflect the new license.
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: 351636
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.
Reviewers: echristo, zturner, mzolotukhin, lhames
Reviewed By: echristo
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45135
llvm-svn: 328940
Summary: unique_lock has the overhead of tracking ownership status and the owner.
Reviewers: grimar, zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D44698
llvm-svn: 328271
parallel_for_each_n splits a given task into small pieces of tasks and then
passes them to background threads managed by a thread pool to process them
in parallel. TaskGroup then waits for all tasks to be done, which is done by
TaskGroup's destructor.
In the previous code, all tasks were passed to background threads, and the
main thread just waited for them to finish their jobs. This patch changes
the logic so that the main thread processes a task just like other
worker threads instead of just waiting for workers.
This patch improves the performance of parallel_for_each_n for a task which
is too small that we do not split it into multiple tasks. Previously, such task
was submitted to another thread and the main thread waited for its completion.
That involves multiple inter-thread synchronization which is not cheap for
small tasks. Now, such task is processed by the main thread, so no inter-thread
communication is necessary.
Differential revision: https://reviews.llvm.org/D36607
llvm-svn: 311312
