Mutex supports reader access, OS blocking, spinning,
portable and smaller than BlockingMutex.
Overall it's supposed to be better than RWMutex/BlockingMutex.
Replace RWMutex/BlockingMutex with Mutex.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D106936
Now that sanitizer_common mutex has feature-parity with tsan mutex,
switch tsan to the sanitizer_common mutex and remove tsan's custom mutex.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D106379
We currently have 3 different mutexes:
- RWMutex
- BlockingMutex
- __tsan::Mutex
RWMutex and __tsan::Mutex are roughly the same,
except that tsan version supports deadlock detection.
BlockingMutex degrades better under heavy contention
from lots of threads (blocks in OS), but much slower
for light contention and has non-portable performance
and has larger static size and is not reader-writer.
Add a new mutex that combines all advantages of these
mutexes: it's reader-writer, has fast non-contended path,
supports blocking to gracefully degrade under higher contention,
has portable size/performance.
For now it's named Mutex2 for incremental submission. The plan is to:
- land this change
- then move deadlock detection logic from tsan
- then rename it to Mutex and remove tsan Mutex
- then typedef RWMutex/BlockingMutex to this mutex
SpinMutex stays as separate type because it has faster fast path:
1 atomic RMW per lock/unlock as compared to 2 for this mutex.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D106231
Semaphore is a portable way to park/unpark threads.
The plan is to use it to implement a portable blocking
mutex in subsequent changes. Semaphore can also be used
to efficiently wait for other things (e.g. we currently
spin to synchronize thread creation and start).
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D106071
See https://reviews.llvm.org/D58620 for discussion, and for the commands
I ran. In addition I also ran
for f in $(svn diff | diffstat | grep .cc | cut -f 2 -d ' '); do rg $(basename $f) . ; done
and manually updated references to renamed files found by that.
llvm-svn: 367467
Dmitry Vyukov