Profiling memory accesses - which counters overlap with which?

Profiling memory accesses - which counters overlap with which?

Hi!

I have some Perl scripts that implement some of the top-level vtune profiling for sandy bridge (and SB Xeon.)

Noticably:

* % cycles spent LLC miss: ~ 53%

* % cycles spent doing DTLB walks: ~ 10%

* % cycles spent accessing data modified by another core: ~ 3.5%

My question: when doing DTLB walks (DTLB_LOAD_MISSES.WALK_DURATION) and cycles spent hit'ing on data modified by another core (MEM_LOAD_UOPS_LLC_HIT_RETIRED.XSNP_HITM) - do these overlap in any way with the LLC_MISS (ie memory access - MEM_LOAD_UOPS_MISC_RETIRED.LLC_MISS) ? Partially overlap? Don't overlap at all?

I'm especially interested in whether the DTLB walks count towards MEM_LOAD_UOPS_MISC_RETIRED.LLC_MISS.

Thanks!

-adrian

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