brpc: bthread使用

使用bthread并发编程

#include <gflags/gflags.h>
#include <butil/logging.h>
#include <bthread/bthread.h>static void* func(void* args) {std::string* num = static_cast<std::string*>(args);for(int i = 0; i < 5; i++) {LOG(INFO) << *num;bthread_usleep(1000);}return NULL;
}int main() {bthread_t th1, th2;std::string a = "bthread:A", b = "bthread:B", c = "bthread:C";if (bthread_start_background(&th1, NULL, func, static_cast<void*>(&a)) != 0) {LOG(ERROR) << "Fail to create bthread for part1";}if (bthread_start_background(&th2, NULL, func, static_cast<void*>(&b)) != 0) {LOG(ERROR) << "Fail to create bthread for part2";}func(static_cast<void*>(&c));bthread_join(th1, NULL);bthread_join(th2, NULL);
}

thread 栈切换事例

#include <bthread/context.h>
#include <iostream>::bthread_fcontext_t fc1;
::bthread_fcontext_t fc2;
::bthread_fcontext_t fc_tmp;
intptr_t  g_num1 = 0;
intptr_t  g_num2 = 0;static void jumper1(intptr_t param) {for(int i = 0; i < 9; i++) {printf("context1: g_num1 = %ld, then jump to context2\n", ++g_num1);::bthread_jump_fcontext(&fc1, fc2, 0);}// 最后结尾，jump到原始上下文中，继续执行printf("context1: g_num1 = %ld, finally, jump to main\n", ++g_num1);::bthread_jump_fcontext(&fc1, fc_tmp, 0);
}
static void jumper2(intptr_t param) {for(int i = 0; i < 10; i++) {printf("context2: g_num2 = %ld, then jump to context1\n", ++g_num2);::bthread_jump_fcontext(&fc2, fc1, 0);}
}int main() {static const std::size_t stack_size = 8192;// 创建两个上下文void *sp1 = ::malloc(stack_size);fc1 = ::bthread_make_fcontext((char*)sp1 + stack_size, stack_size, jumper1);void *sp2 = ::malloc(stack_size);fc2 = ::bthread_make_fcontext((char*)sp2 + stack_size, stack_size, jumper2); // 将当前上下文保存到fc_tmp，并切换上下为fc2::bthread_jump_fcontext(&fc_tmp, fc2, 0);printf("done\n");::free(sp1);::free(sp2);return 0;
}

ExecutionQueue 的使用

ExecutionQueue是一个mpsc队列，即线程安全的多生产者单消费者队列

#include <bthread/execution_queue.h>
#include <bthread/bthread.h>
class DemoTask {
public:void run(int);
};void DemoTask::run(int count) {LOG(INFO) << "DemoTask::run(" << count << ")";
}int comsume(void *meta, bthread::TaskIterator<DemoTask*> &iter) {if(iter.is_queue_stopped()) {return 0;}int count = 0;for(; iter; ++iter) {DemoTask *task = *iter;task->run(++count);}return 0;
}int main() {bthread::ExecutionQueueId<DemoTask*> exe_queue;int ret = bthread::execution_queue_start(&exe_queue, nullptr, comsume, nullptr);DemoTask *task = new DemoTask();ret = bthread::execution_queue_execute(exe_queue, task);bthread_usleep(10);
}