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)