In Paul McKenny's famous paper "Memory Barriers: A Hardware View for Software Hackers" 3.3 Store Buffers and Memory Barriers To see the second complication, a violation of global memory ...

In MESI protocol you write to the cache line only when holding it in the Exclusive/Modified state. To acquire the Exclusive state, you send an Invalidate request to all the cores holding the same c...

This is about cache coherency protocol across different layers of cache. My understanding(X86_64) about L1 is that, it is owned exclusively by a core and L2 is between 2 cores and L3 for all the co...

x86 guarantees a total order over all stores due to its TSO memory model. My question is if anyone has an idea how this is actually implemented. I have a good impression how all the 4 fences are im...

I am somewhat confused with what how cache coherence systems function in modern multi core CPU. I have seen that snooping based protocols like MESIF/MOESI snooping based protocols have been used in...

For my bachelor thesis I have to analyse the effecs of False Sharing on multicore systems. So looking for the different cache-coherence-protocol-types I have come across on Wikipedia that Intel has...

In regards to std::atomic, the C++11 standard states that stores to an atomic variable will become visible to loads of that variable in a "reasonable amount of time". From 29.3p13: Implementat...

I understand that the MESI protocol successfully guarantees the same view of memory (caches) for different cores. My question comes from the fact that during writing MESI guarantees that the cache ...

I like to know more details of MESI in intel broadwell . Suppose A cpu socket has 6 cores core 0 to core 5 , each of them has their own L1$ and L2$ and share L3$ , there are a var X in shared mem...

I have the following processes , I try to make ProcessB very low latency so I use tight loop all the time and isolate cpu core 2 . global var in shared memory : int bDOIT ; typedef struct XYZ_ { ...

Core A writes value x to storebuffer, waiting invalid ack and then flushes x to cache. Does it wait only one ack or wait all acks ? And how does it konw how many acks in all CPUs ?

I was wondering what benefits MOESI has over the MESI cache coherency protocol, and which protocol is currently favored for modern architectures. Oftentimes benefits don't translate to implementati...

Can there be a case in a cache employing a MESI protocol (has l1 and l2 inclusivity employed) where l2 can send an invalid instruction to an already invalid line in l1.

I'm wondering about MESI protocol implementation of writing with the allocation on write miss policy. Let's say that we have write request and got cache miss with no other copies of cache line. Thi...

What is the purpose of the x86 LOCK prefix, if the MESI protocol prevents other cores from writing to "exclusive"-ly owned data anyway? I am getting a little confused between what LOCK provides a...

I am learning cache coherency now, but I don't quite understand what's the function of Exclusive state in MESI protocol, as I think MSI is also work well.

In C#, this is the standard code for invoking an event in a thread-safe way: var handler = SomethingHappened; if(handler != null) handler(this, e); Where, potentially on another thread, the com...

I've read this topic: C# Thread safe fast(est) counter and have implemented this feature in my parallel code. As far as I can see it all works fine, however it has measurably increased the processi...

I was reading about the MESI snooping cache coherence protocol, which I guess is the protocol that is used in modern multicore x86 processors (please correct me if I'm wrong). Now that article says...