LIBPFM(3) Linux Programmer's Manual LIBPFM(3)

libpfm_intel_icx_unc_cha - support for Intel IcelakeX Server CHA uncore PMU

#include <perfmon/pfmlib.h>

PMU name: icx_unc_cha[0-39]
PMU desc: Intel IcelakeX CHA uncore PMU

The library supports the Intel IcelakeX CHA (coherency and home agent) uncore PMU. There is one CHA-box PMU per physical core. Therefore there are up forty identical CHA PMU instances numbered from 0 up to possibly 39. On dual-socket systems, the number refers to the CHA PMUs on the socket where the program runs.

Each CHA PMU implements 4 generic counters.

The following modifiers are supported on Intel IcelakeX CHA uncore PMU:

Enable edge detection, i.e., count only when there is a state transition from no occurrence of the event to at least one occurrence. This modifier must be combined with a threshold modifier (t) with a value greater or equal to one. This is a boolean modifier.
Set the threshold value. When set to a non-zero value, the counter counts the number of CHA clockticks in which the number of occurrences of the event is greater or equal to the threshold. This is an integer modifier with values in the range [0:255].
Invert the threshold (t) test from strictly greater than to less or equal to. This is a boolean modifier. 

Stephane Eranian <eranian@gmail.com>
November, 2023