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

NAME

       libpfm_intel_nhm - support for Intel Nehalem core PMU

SYNOPSIS

       #include <perfmon/pfmlib.h>

       PMU name: nhm
       PMU desc: Intel Nehalem
       PMU name: nhm_ex
       PMU desc: Intel Nehalem EX

DESCRIPTION

       The  library supports the Intel Nehalem core PMU. It should be noted that this PMU model only covers the each core's PMU and not the socket
       level PMU. It is provided separately. Support is provided for the Intel Core i7 and Core i5 processors.

MODIFIERS

       The following modifiers are supported on Intel Nehalem 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_INST_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 event
       The  library is able to encode the OFFCORE_RESPONSE_0 event. This is a special event because it needs a second MSR (0x1a6) to be programmed
       for the event to count properly. Thus two values are necessary. The first value can be programmed on any of the generic counters. The  sec-
       ond value goes into the dedicated MSR (0x1a6).

       The OFFCORE_RESPONSE event is exposed as a normal event with several umasks which are divided in two groups: request and response. The user
       must provide at least one umask from each group.  For instance, OFFCORE_RESPONSE_0:ANY_DATA:LOCAL_DRAM.

       When using pfm_get_event_encoding(), two 64-bit values are returned. The first value corresponds to what needs to be programmed into any of
       the generic counters. The second value must be programmed into the dedicated MSR (0x1a6).

       When  using  an	OS-specific  encoding  routine,  the way the event is encoded is OS specific. Refer to the corresponding man page for more
       information.

AUTHORS

       Stephane Eranian <eranian@gmail.com>

								  September, 2009							 LIBPFM(3)