Method signal_task

src/bthread/task_control.cpp:564–592

}

void TaskControl::signal_task(int num_task, bthread_tag_t tag) {
    if (num_task <= 0) {
        return;
    }
    // TODO(gejun): Current algorithm does not guarantee enough threads will
    // be created to match caller's requests. But in another side, there's also
    // many useless signalings according to current impl. Capping the concurrency
    // is a good balance between performance and timeliness of scheduling.
    if (num_task > 2) {
        num_task = 2;
    }
    auto& pl = tag_pl(tag);
    size_t start_index = butil::fmix64(pthread_numeric_id()) % _pl_num_of_each_tag;
    for (size_t i = 0; i < _pl_num_of_each_tag && num_task > 0; ++i) {
        num_task -= pl[start_index].signal(1);
        if (++start_index >= _pl_num_of_each_tag) {
            start_index = 0;
        }
    }
    if (num_task > 0 &&
        FLAGS_bthread_min_concurrency > 0 &&    // test min_concurrency for performance
        _concurrency.load(butil::memory_order_relaxed) < FLAGS_bthread_concurrency) {
        // TODO: Reduce this lock
        BAIDU_SCOPED_LOCK(g_task_control_mutex);
        if (_concurrency.load(butil::memory_order_acquire) < FLAGS_bthread_concurrency) {
            add_workers(1, tag);
        }
    }
}

void TaskControl::print_rq_sizes(std::ostream& os) {
    size_t ngroup = 0;