Using perf to monitor raw event counters

Question

I am trying to measure certain hardware events on a (Intel Xeon) machine with multiple (physical) processors. Specifically, I wish to know how many requests are issued for readi

Answer 1

There are several libraries which can be helpful to work with raw PMU events.

perf's own wiki https://perf.wiki.kernel.org/index.php/Tutorial#Events recommends perf list --help man page for info about raw events encoding. And modern perf versions will list raw events as part of perf list output ("... if linked against the libpfm4 library, provides some short description of the events."). perf list --details will also print raw ids and masks of events.

Bojan Nikolic has "How to monitor the full range of CPU performance events" blog article about libpfm4 (perfmon2) lib usage to encode raw events for perf with help of showevtinfo and check_events tools.

There is also perf python wrapper ocperf which accepts intel's event names. It is written by Andi Kleen (Intel Open Source Technology Center) as part of pmu-tools set of utilities (LWN post from 2013, event lists by intel at https://download.01.org/perfmon/). There is a demo of ocperf (2011) http://halobates.de/modern-pmus-yokohama.pdf:

ocperf
•Perf wrapper to support Intel specific events
•Allows symbolic events and some additional events

    ocperf record -a −e offcore_response.any_data.remote_dram_0 sleep 10

PAPI library also has tool to explore raw events with some descriptions - papi_native_avail.