Profiling on Modern CPUs

Profiling isn't just “count instructions, look for hotspots” anymore. Between the superscalar-ness, the multi-core-ness, the shared-cache-ness, the shared-bus-ness, the hierarchical memory-ness and a lot of other -ness'es, things get a little.. special.

This is (for now) a reading list and set of notes of what I've come across whilst exploring what's going on with modern intel hardware.

There are a few things to try and make .. easier to do in PMC:

A system overview (eg GNU/perf 'perf stat') that gives simple overviews for things like general instruction counts and efficiencies, cache thrashing, resource stalls, etc
Make it much easier to establish where certain classes of bottlenecks are when profiling (again - bus / cache bottlenecks, cache thrashing, resource stalls)
A much nicer way of summarising / analysing counters - right now it's per-CPU and on larger CPU machines this gets very unwieldy very quickly
A machine-summarised version of the counter output (with timestamping) so it can be fed into external processing scripts