# libpfm_intel_snbep_unc_cbo

## NAME



           libpfm_intel_snbep_unc_cbo - support for Intel Sandy Bridge-EP C-
           Box uncore PMU
    


## SYNOPSIS



           **#include <perfmon/pfmlib.h>**
    
           **PMU name: snbep_unc_cbo[0-7]**
           **PMU desc: Intel Sandy Bridge-EP C-Box uncore PMU**
    


## DESCRIPTION



           The library supports the Intel Sandy Bridge C-Box (coherency
           engine) uncore PMU.  This PMU model only exists on Sandy Bridge
           model 45. There is one C-box PMU per physical core. Therefore
           there are eight identical C-Box PMU instances numbered frmo 0 to
           7. On dual-socket systems, the number refers to the C-Box PMU on
           the socket where the program runs. For instance, if running on
           CPU8, then snbep_unc_cbo0 refers to the C-Box for physical core 0
           on socket 1. Conversely, if running on CPU0, then the same
           snbep_unc_cbo0 refers to the C-Box for physical core 0 but on
           socket 0.
    
           Each C-Box PMU implements 4 generic counters and a filter register
           used only with certain events and umasks.
    


## MODIFIERS



           The following modifiers are supported on Intel Sandy Bridge C-Box
           uncore PMU:
    
           **i** Invert the meaning of the event. The counter will now count
                  C-Box 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
                  threshold modifier (t) with a value greater or equal to
                  one.  This is a boolean modifier.
    
           **t** Set the threshold value. When set to a non-zero value, the
                  counter counts the number of C-Box 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].
    
           **nf** Node filter. Certain events, such as UNC_C_LLC_LOOKUP,
                  UNC_C_LLC_VICTIMS, provide a **NID** umask.  Sometimes the **NID**
                  is combined with other filtering capabilities, such as
                  opcodes.  The node filter is an 8-bit max bitmask. A node
                  corresponds to a processor socket. The legal values
                  therefore depend on the underlying hardware configuration.
                  For dual-socket systems, the bitmask has two valid bits
                  [0:1].
    
           **cf** Core Filter. This is a 3-bit filter which is used to filter
                  based on physical core origin of the C-Box request.
                  Possible values are 0-7. If the filter is not specified,
                  then no filtering takes place.
    
           **tf** Thread Filter. This is a 1-bit filter which is used to
                  filter C-Box requests based on logical processor (hyper-
                  thread) identification. Possibles values are 0-1. If the
                  filter is not specified, then no filtering takes place.
    


## Opcode filtering



           Certain events, such as UNC_C_TOR_INSERTS supports opcode matching
           on the C-BOX transaction type. To use this feature, first an
           opcode matching umask must be selected, e.g., MISS_OPCODE.
           Second, the opcode to match on must be selected via a second umask
           among the OPC_* umasks.  For instance,
           UNC_C_TOR_INSERTS:OPCODE:OPC_RFO, counts the number of TOR
           insertions for RFO transactions.
    
           Opcode matching may be combined with node filtering with certain
           umasks. In general the filtering support is encoded into the umask
           name, e.g., NID_OPCODE supports both node and opcode filtering.
           For instance, UNC_C_TOR_INSERTS:NID_OPCODE:OPC_RFO:nf=1.
    


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