CACHE COHERENCE PROBLEM SOLUTIONS

[Audio] Hello everyone! In my presentation I will tell you about the Cache Coherence Problem and its solutions..

[Audio] First, I'll explain what the Cache Coherence problem is. Next, I will present the main types of its solutions, Software and Hardware level solutions. I will show you the hardware level solutions in more detail. We'll look at the directory based cache coherence protocols and snoopy protocols..

[Audio] In a multiprocessor system, all the processors in the system share the main memory via a bus. For higher performance each processor implements its own cache. Cache coherence refers to the problem of keeping the data in these caches consistent. The main problem is dealing with writes by a processor..

[Audio] Let me illustrate it. In a multi-processor system every core has its own independent memory storage, also there are some memory storages which are shared among all of them. Here we have four different processors, namely P1, P2, P3 and P4. All these processors have their own private caches. The shared storage is the main memory, which is connected with the processor with the help of the system bus. Additionally all the different private caches they are interconnected with the help of the internal bus..