(These are old notes for relatively old systems — I just found this in my “drafts” folder and decided to switch the status to “public” so I can find it again!) Some notes on how to determine the DRAM and Memory Controller configuration for a system using AMD Opteron/Phenom or… read more
Computer Hardware
Counting Stall Cycles on the Intel Sandy Bridge Processor
Intuition might suggest that defining what a “stall cycle” is on a processor should be relatively straightforward. For some processors, this is actually the case — particularly in-order processors with a very small number of execution units and a very small number of non-pipelined instructions. For modern out-of-order processors, coming… read more
Notes on the mystery of hardware cache performance counters
In response to a question on the PAPI mailing list, I scribbled some notes to try to help users understand the complexity of hardware performance counters for cache accesses and cache misses, and thought they might be helpful here…. For any interpretation of specific hardware performance counter events, it is… read more