The Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 3 (3A, 3B & 3C): System Programming Guide,
Table 19-2. Non-Architectural Performance Events In the Processor Core of ThirdGeneration Intel Core i7, i5, i3 Processors
L2_RQSTS.PF_HIT Counts all L2 HW prefetcher requests that hit L2.
L2_RQSTS.PF_MISS Counts all L2 HW prefetcher requests that missed L2.
However I am unsure what that means.
1) Does hit mean that the L2 prefetcher decided to get some data, but found that it was already in L2? In case the requested data was not present or invalid in L2, does that mean it was a miss? Or is this a prefetcher miss, i.e. the prefetched data was never used before it was evicted?
2) When there was a miss, does that mean that the prefetcher will copy data to L2 every time and if there was a hit it will not? Or what does this entail?
Thanks for your help,