libpfm_intel_bdx_unc_pcu(3) — Linux manual page

NAME \| SYNOPSIS \| DESCRIPTION \| MODIFIERS \| Frequency band filtering \| AUTHORS \| COLOPHON

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

NAME top

       libpfm_intel_bdx_unc_pcu - support for Intel Broadwell Server
       Power Controller Unit (PCU) uncore PMU

SYNOPSIS top

       #include <perfmon/pfmlib.h>

       PMU name: bdx_unc_pcu
       PMU desc: Intel Broadwell Server PCU uncore PMU

DESCRIPTION top

       The library supports the Intel Broadwell Server Power Controller
       Unit uncore PMU.  This PMU model only exists on various Broadwell
       server models (79, 86).

MODIFIERS top

       The following modifiers are supported on Intel Broadwell server
       PCU uncore PMU:

       e      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.

       t      Set the threshold value. When set to a non-zero value, the
              counter counts the number of HA cycles 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 [0:15].

       i      Invert the meaning of the threshold or edge filter. If set,
              the event counts when strictly less than N occurrences
              occur per cycle if threshold is set to N. When invert is
              set, then threshold must be set to non-zero value. If set,
              the event counts when the event transitions from occurring
              to not occurring (falling edge) when edge detection is set.
              This is a boolean modifier

       ff     Enable frequency band filtering. This modifier applies only
              to the UNC_P_FREQ_BANDx_CYCLES events, where x is [0-3].
              The modifiers expects an integer in the range [0-255]. The
              value is interpreted as a frequency value to be multiplied
              by 100Mhz. Thus if the value is 32, then all cycles where
              the processor is running at 3.2GHz and more are counted.

Frequency band filtering top

       There are 3 events which support frequency band filtering, namely,
       UNC_P_FREQ_BAND0_CYCLES, UNC_P_FREQ_BAND1_CYCLES,
       UNC_P_FREQ_BAND2_CYCLES, UNC_P_FREQ_BAND3_CYCLES. The frequency
       filter (available via the ff modifier) is stored into a PMU shared
       register which hold all 4 possible frequency bands, one per event.
       However, the library generate the encoding for each event
       individually because it processes events one at a time. The caller
       or the underlying kernel interface may have to merge the band
       filter settings to program the filter register properly.

AUTHORS top

       Stephane Eranian <[email protected]>

COLOPHON top

       This page is part of the perfmon2 (a performance monitoring
       library) project.  Information about the project can be found at
       ⟨http://perfmon2.sourceforge.net/⟩.  If you have a bug report for
       this manual page, send it to [email protected].
       This page was obtained from the project's upstream Git repository
       ⟨git://git.code.sf.net/p/perfmon2/libpfm4 perfmon2-libpfm4⟩ on
       2025-08-11.  (At that time, the date of the most recent commit
       that was found in the repository was 2025-06-29.)  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a
       mail to [email protected]

                                June, 2017                      LIBPFM(3)