NAME

       libpfm_intel_nhm - support for Intel Nehalem core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: nhm
       PMU desc: Intel Nehalem
       PMU name: nhm_ex
       PMU desc: Intel Nehalem EX

DESCRIPTION

       The  library  supports  the Intel Nehalem 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.

MODIFIERS

       The following modifiers are supported on Intel Nehalem processors:

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

       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 MEM_INST_RETIRED:LATENCY_ABOVE_THRESHOLD event.
              This is an integer attribute that must be in the range [1:65535].  It  is  required
              for this event.  Note that the event must be used with precise sampling (PEBS).

OFFCORE_RESPONSE event

       The  library  is  able  to  encode  the  OFFCORE_RESPONSE_0 event. This is a special event
       because it needs a second MSR (0x1a6) to be programmed for the event  to  count  properly.
       Thus  two  values  are  necessary. The first value can be programmed on any of the generic
       counters. The second value goes into the dedicated MSR (0x1a6).

       The OFFCORE_RESPONSE event is exposed as a normal event  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 dedicated MSR (0x1a6).

       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

       Stephane Eranian <eranian@gmail.com>

                                         September, 2009                                LIBPFM(3)