What is "Block","Nest" and "BC_MSHR","C_MSHR"?

[ArcheyChen]

Hello,I'm reading the code,and don't understand why we should block and nest some request. and why there are two higher priority MSHR aloneside others?

[CircuitCoder]

I'm also currently reading the code. @sequencer actually has one fork that has plenty of comment at https://github.com/sequencer/block-inclusivecache-sifive

IMHO the name MSHR is a little bit inappropriate (and has caused a lot of confusion for me). It's not corresponding outstanding requests sent to cache's slaves (e.g. the main memory). Instead it's corresponding to outstanding requests from cache's masters (e.g. L1 caches). So the blocking is to enforce TL channel priority.