__sync_synchronize()是发出一个full barrier,简单来说就是不允许将这条语句之前的内存读写指令放在这条之后,也不允许将这条语句之后的内存读写指令放在这条指令之前。 由于编译器翻译成汇编代码是乱序的,在xchg获得锁之前,后面关于 debug 的语句可能提前执行,这条指令就能保证需要等到获取锁之后,才会执行 debug ...
write1(dev.register_size,size);write1(dev.register_addr,addr);write1(dev.register_cmd,READ);__sync_synchronize();write1(dev.register_control,GO); memory barrier有几种类型: acquire barrier : 不允许将barrier之后的内存读取指令移到barrier之前(linux kernel中的wmb())。 release barrier : 不允许将...
Although this code is not (time-)efficient, as far as I can see the code is valid, because the two threads only synchronize on the global variable value in a way such that no undefined behaviour could result. The only problem might occur at using the vector concurren...
0 You seem to be doing well by calling pthread_join for the threads you aim to synchronize, because that assures that your main thread will wait until the other threads are done: The problem seems to be that you are not calling pthread_exit in the threads that are to be synchronized: ...
#define barrier() (__sync_synchronize()) /* 原子获取 */ #define AO_GET(ptr) ({ __typeof__(*(ptr)) volatile *_val = (ptr); barrier(); (*_val); }) /* 原子设置 */ #define AO_SET(ptr, value) ((void)__sync_lock_test_and_set((ptr), (value))) ...
SafepointSynchronize::is_at_safepoint()){// 未在安全点执行,可能是撤销或重新偏向。BiasedLocking::Conditioncond=BiasedLocking::revoke_and_rebias(obj,attempt_rebias,THREAD);// 如果重新偏向成功,则退出该过程。if(cond==BiasedLocking::BIAS_REVOKED_AND_REBIASED){return;}}else{assert(!attempt_rebias,...
__sync_synchronize (...) This builtin issues a full memory barrier. type __sync_lock_test_and_set (type *ptr, type value, ...) This builtin, as described by Intel, is not a traditional test-and-set operation, but rather an atomic exchange operation. It writes value into *ptr, ...
vC); 5 c.discard_data(); 6 parallel_for_each(c.extent, [=](index<2>idx) restrict(amp) 7 { 8 int row = idx[0]; int col = idx[1]; 9 int sum = 0; 10 for(int i = 0; i
为了避免主机时间因为长期运作下所导致的时间偏差,进行时间同步(synchronize)的工作是非常必要的。Linux系统下,一般使用ntp服务器来同步不同机器的时间。一台机器,可以同时是ntp服务器和ntp客户机。 2.1 ntpdate命令实现 ntpdate 安装: yum install ntpdate -y# Centos系统=== sudo apt install ntpdate# Ubuntu系统...
CMFCTabCtrl::SetTabMaxWidth 指定选项卡式窗口中的最大选项卡宽度。 CMFCTabCtrl::StopResize 终止选项卡控件上的当前重设大小操作。 CMFCTabCtrl::SwapTabs 交换一对选项卡。 (替代 CMFCBaseTabCtrl::SwapTabs。) CMFCTabCtrl::SynchronizeScrollBar 在显示平面选项卡的选项卡控件上绘制水平滚动条。数据...