NAME

       libpfm_intel_slm - support for Intel Silvermont core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: slm
       PMU desc: Intel Silvermont

DESCRIPTION

       The library supports the Intel Silvermont core PMU.

MODIFIERS

       The following modifiers are supported on Intel Silvermont 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].

OFFCORE_RESPONSE events

       Intel Silvermont provides two offcore_response events: 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 event 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 Silvermont, 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.
       The library provides a default umask per category if not provided by the user.

       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:NON_DRAM:ANY_RESPONSE

       OFFCORE_RESPONSE_0:ANY_RFO:L2_HIT:SNOOP_ANY:ANY_RESPONSE

AUTHORS

       Stephane Eranian <eranian@gmail.com>

                                                 November, 2013                                        LIBPFM(3)