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C/C++11 mappings to processorsThis document summarises some known mappings of C/C++11 atomic operations to x86, PowerPC, ARMv7, ARMv8, and Itanium instruction sequences. These are collected for disc...

当用C/C++编写无锁代码时，一定要小心谨慎，以保证正确的内存顺序。不然的话，会发生一些诡异的事情。Intel在x86/x64体系结构手册的Volume 3, §8.2.3 中列出了一些可能会发生的诡异的事情。这里介绍其中一个最简单的例子。假设在内存中有两个整型变量x和y，都初始化为0。两个处理器并行执行下面的机器码：不要被上面的汇编代码给吓坏了。这个例子的确是阐述CPU执行顺序的...

10多年前的程序员对处理器乱序执行和内存屏障应该是很熟悉的,但随着计算机技术突飞猛进的发展,我们离底层原理越来越远,这并不是一件坏事,但在有些情况下了解一些底层原理有助于我们更好的工作,比如现代高级语言多提供了多线程并发技术,如果不深入下来,那么有些由多线程造成问题就很难排查和理解.今天准备来聊聊乱序执行技术和内存屏障.为了能让大多数人理解,这里省略了很多不影响理解的旁枝末节,但由于我个人水平...

在C++11标准原子库中，大多数函数接收一个memory_order参数：  enum memory_order { memory_order_relaxed, memory_order_consume, memory_order_acquire, memory_order_release, memory_order_acq_rel,...

Acquire and Release SemanticsGenerally speaking, in lock-free programming, there are two ways in which threads can manipulate shared memory: They can compete with each other for a resource, or they ...

Acquire and Release SemanticsGenerally speaking, in lock-free programming, there are two ways in which threads can manipulate shared memory: They can compete with each other for a resource, or they ...

浅谈Memory Reordering  Memory ordering在我们编写的 C/C++代码和它被在 CPU 上运行,按照一些规则,代码的内存交互会被乱序.内存乱序同时由编译器(编译时候)和处理器(运行时)造成,都为了使代码运行的更快.被编译开发者和处理器制造商遵循的中心内存排序准则是:不能改变单线程程序的行为.因为这条规则,在写单线程代码时内存乱序被普...

https://git.project-hobbit.eu/dj16/ricec/blob/c9d3dceb1c3b1c03a42077e0461e3ce5a2615a51/data/atomicops.h#L248// ©2013-2016 Cameron Desrochers.// Distributed under the simplified BSD license (see th...

https://stackoverflow.com/questions/18576986/does-the-semantics-of-stdmemory-order-acquire-requires-processor-instruction7down votefavorite4It is known that on x86 for the operations load() and ...