> > >... could be polluting all your processor caches a lot > >more than you were experiencing previously on 3 CPs, which could lead to > >increased overheads in the OS managing higher levels of cache-misses under > >the covers. > > The operating system does not get involved in cache misses. > When the processor references storage that is not in the > most local cache, the hardware retrieves it from the next > level cache, if it is available there. If not, it tries the next > level and the next. A z196 has a 4 level cache. IIRC a z10 > has 3 levels of cache. If it can't be found in any cache, > main storage is referenced. This all done entirely by the > hardware, and it results in the instruction requiring more > time to execute. > > To look at it another way, cache exists because main storage > is very slow compared to the processor speed. Without > cache, the processor would not be able to execute > instructions nearly as fast as it could. Cache allows data > from main storage to be kept very close to the processor in > extremely fast memory, allowing the processor to execute > instructions as fast as possible. > > Your're right! It was late!! Brain & fingers had a disconnect! I should have written nest (or just 'hardware'), rather than OS.
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