Method concurrency

src/bthread/task_control.h:73–74

Get # of worker threads.

    
    // Get # of worker threads.
    int concurrency() const 
    { return _concurrency.load(butil::memory_order_acquire); }

    int concurrency(bthread_tag_t tag) const 
    { return _tagged_ngroup[tag].load(butil::memory_order_acquire); }