bionic (3) libpfm_intel_skl.3.gz

NAME

       libpfm_intel_skl - support for Intel SkyLake core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: skl
       PMU desc: Intel SkyLake

DESCRIPTION

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

       On SkyLake, the number of generic counters depends on the Hyperthreading (HT) mode.

       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 SkyLake 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.

       fe_thres
              This  modifier  is for the FRONTEND_RETIRED event only. It defines the period in core cycles after
              which the IDQ_*_BUBBLES umask counts. It acts as a threshold, i.e., at least a period  of  N  core
              cycles  where  the  frontend  did  not  deliver X uops. It can only be used with the IDQ_*_BUBBLES
              umasks. If not specified, the default threshold  value  is  1  cycle.  the  valid  values  are  in
              [1-4095].

OFFCORE_RESPONSE events

       Intel   SkyLake   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 SkyLake, 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, 2015                                         LIBPFM(3)