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    SubjectRe: [Perfctr-devel] [patch] Performance Counters for Linux, v4
    > To make life easier for developers not interested in exact measuring, but in
    > cross-platform development, PAPI has introduced "generic" events. These are
    > documented not to be interpretable in a cross-platform manner - and
    > typically consist of aggregation of a number of low-level architecture
    > specific events. Instead a measure as PERF_COUNT_CACHE_REFERENCES tries to
    > create an event set that is a "best effort" for the platform. Typically it
    > would try to count read and write events to L1 and L2, but depending on the

    The point was that L1 and L2/L3 behave so differently in practice
    due to their latency/bandwidth differences (typically L1 is more like a
    slower register file while L3 is more like faster DRAM) that it's unclear
    that any generic event not defining what it means is any useful.

    I could see the point of generic FLC/LLC cache events perhaps,
    but not of a single one lumping these two together.

    But although with multi core it looks like 3 level hierarchies are
    becoming more and more common and also more important to know
    about.

    -Andi

    --
    ak@linux.intel.com


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