bionic (3) libpfm_intel_bdw.3.gz

NAME

       libpfm_intel_bdw - support for Intel Broadwell core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: bdw
       PMU desc: Intel Broadwell

DESCRIPTION

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

       On Broadwell, 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 Broadwell 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:LOAD_LATENCY  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).

       intx   Monitor the event only when executing inside a transactional memory region (in tx). Event does not
              count otherwise. This is a boolean modifiers. Default value is 0.

       intxcp Do not count occurrences of the event when they are inside an aborted transactional memory region.
              This is a boolean modifier. Default value is 0.

OFFCORE_RESPONSE events

       Intel  Broadwell  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  Broadwell, 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>

                                                  October, 2014                                        LIBPFM(3)