NAME

       libpfm_intel_icx - support for Intel IceLakeX core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: icx
       PMU desc: Intel IceLakeX

DESCRIPTION

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

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

       The pfm_get_pmu_info()  function  returns  the  maximum  number  of  generic  counters  in
       num_cntrs.

MODIFIERS

       The following modifiers are supported on Intel IceLakeX 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].

       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 IceLakeX supports two encodings for offcore_response events. In the  library,  these
       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 operating system 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 IceLakeX unlike older processors, the event is treated as a regular event with  a
       flat  set  of  umasks to choose from.  It is not possible to combine the various requests,
       supplier, snoop  bits  anymore.  Therefore  the  library  offers  the  list  of  validated
       combinations as per Intel's official event list.

AUTHORS

       Stephane Eranian <eranian@gmail.com>

                                            May, 2021                                   LIBPFM(3)