LIBPFM(3)						     Linux Programmer's Manual							 LIBPFM(3)

NAME

       libpfm_intel_ivb - support for Intel Ivy Bridge core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: ivb
       PMU desc: Intel Ivy Bridge
       PMU name: ivb_ep
       PMU desc: Intel Ivy Bridge EP

DESCRIPTION

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

       On Ivy Bridge, 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 Ivy Bridge 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 occur-
	      rences 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:LATENCY_ABOVE_THRESHOLD 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).

OFFCORE_RESPONSE events
       Intel Ivy Bridge 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 Ivy Bridge, 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, 2012 							 LIBPFM(3)