libpfm_intel_wsm(3) — Linux manual page


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

NAME         top

       libpfm_intel_wsm - support for Intel Westmere core PMU

SYNOPSIS         top

       #include <perfmon/pfmlib.h>

       PMU name: wsm
       PMU desc: Intel Westmere
       PMU name: wsm_dp
       PMU desc: Intel Westmere DP

DESCRIPTION         top

       The library supports the Intel Westmere core PMU. It should be
       noted that this PMU model only covers the each core's PMU and not
       the socket level PMU. It is provided separately. Support is
       provided for the Intel Core i7 and Core i5 processors (models 37,

MODIFIERS         top

       The following modifiers are supported on Intel Westmere

       u      Measure at user level which includes privilege levels 1,
              2, 3. This corresponds to PFM_PLM3.  This is a boolean

       k      Measure at kernel level which includes privilege level 0.
              This corresponds to PFM_PLM0.  This is a boolean modifier.

       i      Invert the meaning of the event. The counter will now
              count cycles in which the event is not occurring. This is
              a boolean modifier

       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 counter mask modifier (m) with a value greater or equal
              to one.  This is a boolean modifier.

       c      Set the counter mask value. The mask acts as a threshold.
              The counter will count the number of 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 [0:255].

       t      Measure on both threads at the same time assuming hyper-
              threading is enabled. This is a boolean modifier.

       ldlat  Pass a latency threshold to the
              an integer attribute that must be in the range [3:65535].
              It is required for this event.  Note that the event must
              be used with precise sampling (PEBS).

OFFCORE_RESPONSE events         top

       The library is able to encode the OFFCORE_RESPONSE_0 and
       OFFCORE_RESPONSE_1 events.  Those are special events because
       they, each, need a second MSR (0x1a6 and 0x1a7 respectively) to
       be programmed for the event to count properly. Thus two values
       are necessary for each event.  The first value can be programmed
       on any of the generic counters. The second value goes into the
       dedicated MSR (0x1a6 or 0x1a7).

       The OFFCORE_RESPONSE events are exposed as normal events with
       several umasks which are divided in two groups: request and
       response. The user must provide at least one umask from each
       group.  For instance, OFFCORE_RESPONSE_0:ANY_DATA:LOCAL_DRAM.

       When using pfm_get_event_encoding(), two 64-bit values are
       returned. The first value corresponds to what needs to be
       programmed into any of the generic counters. The second value
       must be programmed into the corresponding dedicated MSR (0x1a6 or

       When using an OS-specific encoding routine, the way the event is
       encoded is OS specific. Refer to the corresponding man page for
       more information.

AUTHORS         top

       Stephane Eranian <>

COLOPHON         top

       This page is part of the perfmon2 (a performance monitoring
       library) project.  Information about the project can be found at
       ⟨⟩.  If you have a bug report for
       this manual page, send it to  This page was obtained
       from the project's upstream Git repository
       ⟨git:// perfmon2-libpfm4⟩ on
       2021-08-27.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-08-04.)  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
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       information in this COLOPHON (which is not part of the original
       manual page), send a mail to

                             September, 2009                   LIBPFM(3)