mirrors/yosys
3
0
Fork 0
mirror of https://github.com/YosysHQ/yosys synced 2026-03-28 15:25:49 +00:00
Code Activity

Prevent race on num_active_worker_threads_.

Browse source 
The core issue here is that we need to ensure `num_active_worker_threads_`
is read before incrementing `done_workers`. See the comments
added in this PR to explain why, and why the resulting code is
race-free.
This commit is contained in:
Robert O'Callahan 2026-03-24 22:17:26 +00:00
parent 66306a8ca3
commit 290fb0556d
2 changed files with 28 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

12
kernel/threading.cc
View file

@ -110,7 +110,7 @@ ParallelDispatchThreadPool::~ParallelDispatchThreadPool()
if (num_worker_threads_ == 0)
return;
current_work = nullptr;
num_active_worker_threads_ = num_worker_threads_;
num_active_worker_threads_.store(num_worker_threads_, std::memory_order_relaxed);
signal_workers_start();
wait_for_workers_done();
#endif
@ -119,15 +119,16 @@ ParallelDispatchThreadPool::~ParallelDispatchThreadPool()
void ParallelDispatchThreadPool::run(std::function<void(const RunCtx &)> work, int max_threads)
{
Multithreading multithreading;
num_active_worker_threads_ = num_threads(max_threads) - 1;
if (num_active_worker_threads_ == 0) {
int num_active_worker_threads = num_threads(max_threads) - 1;
if (num_active_worker_threads == 0) {
work({{0}, 1});
return;
}
#ifdef YOSYS_ENABLE_THREADS
num_active_worker_threads_.store(num_active_worker_threads, std::memory_order_relaxed);
current_work = &work;
signal_workers_start();
work({{0}, num_active_worker_threads_ + 1});
work({{0}, num_active_worker_threads + 1});
wait_for_workers_done();
#endif
}
@ -140,7 +141,8 @@ void ParallelDispatchThreadPool::run_worker(int thread_num)
worker_wait_for_start(thread_num);
if (current_work == nullptr)
break;
(*current_work)({{thread_num + 1}, num_active_worker_threads_ + 1});
int num_active_worker_threads = num_active_worker_threads_.load(std::memory_order_relaxed);
(*current_work)({{thread_num + 1}, num_active_worker_threads + 1});
signal_worker_done();
}
signal_worker_done();