I described my challenge in the last post. Let’s ‘s start with our process of ongoing optimization. To be sure, I verify my reasoning with CppMem. I once made a big mistake in my presentation at Meeting C++ 2014.
Now it’s time to put the theory into practice. The job is relatively easy. A small program should undergo ongoing optimization.
CppMem is an interactive tool for exploring the behavior of small code snippets of the C++ memory model. No, it should have to be in the toolbox of each programmer who deals seriously with the memory model.
The relaxed semantics is the end of the scale. The relaxed semantic is the weakest of all memory models and guarantees that the operations on atomic variables are atomic.
Acquire and release fences guarantee similar synchronization and ordering constraints as atomics with acquire-release semantics. Similar because the differences are in the details.
The key idea of a std::atomic_thread_fence is to establish synchronization and ordering constraints between threads without an atomic operation.
A release operation synchronizes-with an acquire operation on the same atomic variable. So we can easily synchronise threads, if … . Today’s post is about the if.
As you may know, I translate in this blog the posts from my German blog into English. My German blog has the 100 posts anniversary. So I started a poll for the next new main topic.
A release operation synchronizes with an acquire operation on the same atomic variable and establishes, in addition, ordering constraints. These are the components to synchronize threads in a performant way in case they act on the same atomic. But how can that work, if two threads share no atomic variable? We want no sequential consistency […]
std::memory_order_consume is the most legendary of the six memory models. That’s for two reasons. On the one hand, std::memory_order_consume is extremely hard to get. On the other hand – that may change in the future – no compiler supports it.