NAME

       libpfm_intel_ivb - support for Intel Ivy Bridge core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: ivb
       PMU desc: Intel Ivy Bridge
       PMU name: ivb_ep
       PMU desc: Intel Ivy Bridge EP

DESCRIPTION

       The library supports the Intel Ivy Bridge core PMU. It should be noted that this PMU model
       only covers each core's PMU and not the socket level PMU.

       On Ivy Bridge, the number of generic counters depends on  the  Hyperthreading  (HT)  mode.
       When  HT is on, then only 4 generic counters are available. When HT is off, then 8 generic
       counters are available. The pfm_get_pmu_info() function  returns  the  maximum  number  of
       generic counters in num_cntrs.

MODIFIERS

       The following modifiers are supported on Intel Ivy Bridge 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_TRANS_RETIRED:LATENCY_ABOVE_THRESHOLD event.
              This is 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

       Intel  Ivy Bridge provides two offcore_response events. They are called OFFCORE_RESPONSE_0
       and OFFCORE_RESPONSE_1.

       Those events need special treatment in the performance monitoring  infrastructure  because
       each  event  uses  an  extra  register  to  store  some  settings.  Thus, in case multiple
       offcore_response events are monitored simultaneously,  the  kernel  needs  to  manage  the
       sharing of that extra register.

       The  offcore_response  events  are  exposed  as  a normal events by the library. The extra
       settings are exposed as regular umasks. The library takes  care  of  encoding  the  events
       according to the underlying kernel interface.

       On  Intel  Ivy Bridge, the umasks are divided into three categories: request, supplier and
       snoop. The user must provide at least one umask for  each  category.  The  categories  are
       shown in the umask descriptions.

       There is also the special response umask called ANY_RESPONSE. When this umask is used then
       it overrides any supplier and snoop umasks. In  other  words,  users  can  specify  either
       ANY_RESPONSE OR any combinations of supplier + snoops.

       In case no supplier or snoop is specified, the library defaults to using ANY_RESPONSE.

       For instance, the following are valid event selections:

       OFFCORE_RESPONSE_0:DMND_DATA_RD:ANY_RESPONSE

       OFFCORE_RESPONSE_0:ANY_REQUEST

       OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:SNOOP_ANY

       But the following are illegal:

       OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:ANY_RESPONSE

       OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:SNOOP_ANY:ANY_RESPONSE

AUTHORS

       Stephane Eranian <eranian@gmail.com>

                                           August, 2012                                 LIBPFM(3)