14 Commits

Author SHA1 Message Date
Fangrui Song
b84d773fd0 [Parallel] Revert sequential task changes
https://reviews.llvm.org/D148728 introduced `bool Sequential` to unify
`execute` and the old `spawn` without argument. However, sequential
tasks might be executed by any worker thread (non-deterministic),
leading to non-determinism output for ld.lld -z nocombreloc (see
https://reviews.llvm.org/D133003).

In addition, the extra member variables have overhead.
This sequential task has only been used for lld parallel relocation
scanning.

This patch restores the behavior before https://reviews.llvm.org/D148728 .

Fix #105958

Pull Request: https://github.com/llvm/llvm-project/pull/109084
2024-09-20 21:15:42 -07:00
Daniil Fukalov
89e6a28867
[NFC] Add explicit #include llvm-config.h where its macros are used. (#106621)
Without these explicit includes, removing other headers, who implicitly
include llvm-config.h, may have non-trivial side effects.
2024-08-30 09:35:06 +02:00
Mehdi Amini
716042a63f
Rename llvm::ThreadPool -> llvm::DefaultThreadPool (NFC) (#83702)
The base class llvm::ThreadPoolInterface will be renamed
llvm::ThreadPool in a subsequent commit.

This is a breaking change: clients who use to create a ThreadPool must
now create a DefaultThreadPool instead.
2024-03-05 18:00:46 -08:00
Alexey Lapshin
629177a819 Fix test bot breakage from 06b617064a997574df409c7d846b6f6b492f5124
This addresses the issue found by: https://lab.llvm.org/buildbot#builders/178/builds/4571
2023-05-04 18:47:59 +02:00
Alexey Lapshin
06b617064a [Support][Parallel] Change check for nested TaskGroups.
This patch changes check for nested TaskGroups so that it allows
parallel execution for TaskGroups. Following pattern would not work
parallelly with current check:

std::function<void()> Fn = [&]() {
  parallel::TaskGroup tg;

  tg.spawn([&]() { });
};

ThreadPool Pool;

Pool.async(Fn);
Pool.async(Fn);

Pool.wait();

One of the TaskGroup would work sequentially as current check
verifies overall number of TaskGroup. Two not nested
TaskGroups can work parallelly but current check prevents this.

Also this patch avoids parallel mode for TaskGroup
in parallel::strategy.ThreadsRequested == 1 case.

This patch is a followup of discussion from D142318

Differential Revision: https://reviews.llvm.org/D148984
2023-05-04 11:28:39 +02:00
Alexey Lapshin
fea8c07356 [Support][Parallel] Add sequential mode to TaskGroup::spawn().
This patch allows to specify that some part of tasks should be
done in sequential order. It makes it possible to not use
condition operator for separating sequential tasks:

TaskGroup tg;
for () {
  if(condition)      ==>   tg.spawn([](){fn();}, condition)
    fn();
  else
    tg.spawn([](){fn();});
}

It also prevents execution on main thread. Which allows adding
checks for getThreadIndex() function discussed in D142318.

The patch also replaces std::stack with std::deque in the
ThreadPoolExecutor to have natural execution order in case
(parallel::strategy.ThreadsRequested == 1).

Differential Revision: https://reviews.llvm.org/D148728
2023-04-26 13:52:26 +02:00
Nico Weber
7effcbda49 Rename parallelForEachN to just parallelFor
Patch created by running:

  rg -l parallelForEachN | xargs sed -i '' -c 's/parallelForEachN/parallelFor/'

No behavior change.

Differential Revision: https://reviews.llvm.org/D128140
2022-06-19 17:49:00 -04:00
Reid Kleckner
c0a922b3db Add parallelTransformReduce and parallelForEachError
parallelTransformReduce is modelled on the C++17 pstl API of
std::transform_reduce, except our wrappers do not use execution policy
parameters.

parallelForEachError allows loops that contain potentially failing
operations to propagate errors out of the loop. This was one of the
major challenges I encountered while parallelizing PDB type merging in
LLD. Parallelizing a loop with parallelForEachError is not behavior
preserving: the loop will no longer stop on the first error, it will
continue working and report all errors it encounters in a list.

I plan to use this to propagate errors out of LLD's
coff::TpiSource::remapTpiWithGHashes, which currently stores errors an
error in the TpiSource object.

Differential Revision: https://reviews.llvm.org/D90639
2020-11-02 16:50:14 -08:00
Reid Kleckner
932f0276ea [Support] Move LLD's parallel algorithm wrappers to support
Essentially takes the lld/Common/Threads.h wrappers and moves them to
the llvm/Support/Paralle.h algorithm header.

The changes are:
- Remove policy parameter, since all clients use `par`.
- Rename the methods to `parallelSort` etc to match LLVM style, since
  they are no longer C++17 pstl compatible.
- Move algorithms from llvm::parallel:: to llvm::, since they have
  "parallel" in the name and are no longer overloads of the regular
  algorithms.
- Add range overloads
- Use the sequential algorithm directly when 1 thread is requested
  (skips task grouping)
- Fix the index type of parallelForEachN to size_t. Nobody in LLVM was
  using any other parameter, and it made overload resolution hard for
  for_each_n(par, 0, foo.size(), ...) because 0 is int, not size_t.

Remove Threads.h and update LLD for that.

This is a prerequisite for parallel public symbol processing in the PDB
library, which is in LLVM.

Reviewed By: MaskRay, aganea

Differential Revision: https://reviews.llvm.org/D79390
2020-05-05 15:21:05 -07:00
Georgii Rymar
1647ff6e27 [ADT/STLExtras.h] - Add llvm::is_sorted wrapper and update callers.
It can be used to avoid passing the begin and end of a range.
This makes the code shorter and it is consistent with another
wrappers we already have.

Differential revision: https://reviews.llvm.org/D78016
2020-04-14 14:11:02 +03:00
Chandler Carruth
2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Adrian Prantl
5f8f34e459 Remove \brief commands from doxygen comments.
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
2018-05-01 15:54:18 +00:00
NAKAMURA Takumi
cf84800ea0 SupportTests: Suppress ParallelTests on mingw for now. Investigating.
llvm-svn: 302766
2017-05-11 06:35:51 +00:00
Zachary Turner
3a57fbd6db [Support] Move Parallel algorithms from LLD to LLVM.
Differential Revision: https://reviews.llvm.org/D33024

llvm-svn: 302748
2017-05-11 00:03:52 +00:00