memory-barriers

问题 I was reading the Intel instruction set guide 64-ia-32 guide to get an idea on memory fences. My question is that for an example with SFENCE, in order to make sure that all store operations are globally visible, does the multi-core CPU parks all the threads even running on other cores till the cache coherence achieved ? 回答1: Barriers don't make other threads/cores wait. They make some operations in the current thread wait , depending on what kind of barrier it is. Out-of-order execution of

问题 I was reading the Intel instruction set guide 64-ia-32 guide to get an idea on memory fences. My question is that for an example with SFENCE, in order to make sure that all store operations are globally visible, does the multi-core CPU parks all the threads even running on other cores till the cache coherence achieved ? 回答1: Barriers don't make other threads/cores wait. They make some operations in the current thread wait , depending on what kind of barrier it is. Out-of-order execution of

问题 I was reading the Intel instruction set guide 64-ia-32 guide to get an idea on memory fences. My question is that for an example with SFENCE, in order to make sure that all store operations are globally visible, does the multi-core CPU parks all the threads even running on other cores till the cache coherence achieved ? 回答1: Barriers don't make other threads/cores wait. They make some operations in the current thread wait , depending on what kind of barrier it is. Out-of-order execution of

问题 As I see from a test-case: https://godbolt.org/z/K477q1 The generated assembly load/store atomic relaxed is the same as the normal variable: ldr and str So, is there any difference between relaxed atomic and normal variable? 回答1: The difference is that a normal load/store is not guaranteed to be tear-free, whereas a relaxed atomic read/write is. Also, the atomic guarantees that the compiler doesn't rearrange or optimise-out memory accesses in a similar fashion to what volatile guarantees.

来源： https://stackoverflow.com/questions/64575705/is-c-singleton-need-memory-barrier-while-using-mutex

来源： https://stackoverflow.com/questions/64575705/is-c-singleton-need-memory-barrier-while-using-mutex

来源： https://stackoverflow.com/questions/63912669/what-does-it-mean-that-two-store-are-seen-in-a-consistent-order-by-other-proces

来源： https://stackoverflow.com/questions/63912669/what-does-it-mean-that-two-store-are-seen-in-a-consistent-order-by-other-proces

来源： https://stackoverflow.com/questions/60119169/what-are-memory-fences-used-for-in-java

来源： https://stackoverflow.com/questions/60119169/what-are-memory-fences-used-for-in-java