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PAPI_derived_event_files - Describes derived event definition file syntax.

Derived Events

PAPI provides the ability to define events whose value will be derived from multiple
native events. The list of native events to be used in a derived event and a formula which
describes how to use them is provided in an event definition file. The PAPI team provides
an event definition file which describes all of the supported PAPI preset events. PAPI
also allows a user to provide an event definition file that describes a set of user
defined events which can extend the events PAPI normally supports.

This page documents the syntax of the commands which can appear in an event definition
file.

General Rules:
· Blank lines are ignored.
· Lines that begin with '#' are comments (they are also ignored).
· Names shown inside < > below represent values that must be provided by the user.
· If a user provided value contains white space, it must be protected with quotes.
Commands:
CPU,<pmuName>
Specifies a PMU name which controls if the PRESET and EVENT commands that follow this
line should be processed. Multiple CPU commands can be entered without PRESET or EVENT
commands between them to provide a list of PMU names to which the derived events that
follow will apply. When a PMU name provided in the list matches a PMU name known to
the running system, the events which follow will be created. If none of the PMU names
provided in the list match a PMU name on the running system, the events which follow
will be ignored. When a new CPU command follows either a PRESET or EVENT command, the
PMU list is rebuilt.

PRESET,<eventName>,<derivedType>,<eventAttr>,LDESC,"<longDesc>",SDESC,"<shortDesc>",NOTE,"<note>"
Declare a PAPI preset derived event.

EVENT,<eventName>,<derivedType>,<eventAttr>,LDESC,"<longDesc>",SDESC,"<shortDesc>",NOTE,"<note>"
Declare a user defined derived event.

Where:

pmuName:
The PMU which the following events should apply to. A list of PMU names supported by
your system can be obtained by running papi_component_avail on your system.

eventName:
Specifies the name used to identify this derived event. This name should be unique
within the events on your system.

derivedType:
Specifies the kind of derived event being defined (see 'Derived Types' below).

eventAttr:
Specifies a formula and a list of base events that are used to compute the derived
events value. The syntax of this field depends on the 'derivedType' specified above
(see 'Derived Types' below).

longDesc:
Provides the long description of the event.

shortDesc:
Provides the short description of the event.

note:
Provides an event note.

baseEvent (used below):
Identifies an event on which this derived event is based. This may be a native event
(possibly with event masks), an already known preset event, or an already known user
event.
Notes:
The PRESET command has traditionally been used in the PAPI provided preset definition
file. The EVENT command is intended to be used in user defined event definition files. The
code treats them the same so they are interchangeable and they can both be used in either
event definition file.
Derived Types:
This describes values allowed in the 'derivedType' field of the PRESET and EVENT commands.
It also shows the syntax of the 'eventAttr' field for each derived type supported by these
commands. All of the derived events provide a list of one or more events which the derived
event is based on (baseEvent). Some derived events provide a formula that specifies how to
compute the derived events value using the baseEvents in the list. The following derived
types are supported, the syntax of the 'eventAttr' parameter for each derived event type
is shown in parentheses.

NOT_DERIVED (<baseEvent>):
This derived type defines an alias for the existing event 'baseEvent'.

DERIVED_ADD (<baseEvent1>,<baseEvent2>):
This derived type defines a new event that will be the sum of two other events. It has
a value of 'baseEvent1' plus 'baseEvent2'.

DERIVED_PS (PAPI_TOT_CYC,<baseEvent1>):
This derived type defines a new event that will report the number of 'baseEvent1'
events which occurred per second. It has a value of ((('baseEvent1' * cpu_max_mhz) *
1000000 ) / PAPI_TOT_CYC). The user must provide PAPI_TOT_CYC as the first event of
two events in the event list for this to work correctly.

DERIVED_ADD_PS (PAPI_TOT_CYC,<baseEvent1>,<baseEvent2>):
This derived type defines a new event that will add together two event counters and
then report the number which occurred per second. It has a value of (((('baseEvent1' +
baseEvent2) * cpu_max_mhz) * 1000000 ) / PAPI_TOT_CYC). The user must provide
PAPI_TOT_CYC as the first event of three events in the event list for this to work
correctly.

DERIVED_CMPD (<baseEvent1>,<baseEvent2):
This derived type works much like the NOT_DERIVED type. It is rarely used and it looks
like the code just returns a single value returned from the kernel. There is no
calculation done to compute this events value. Not sure why multiple input events seem
to be needed to use this event type.

DERIVED_SUB (<baseEvent1>,<baseEvent2>):
This derived type defines a new event that will be the difference between two other
events. It has a value of 'baseEvent1' minus 'baseEvent2'.

DERIVED_POSTFIX (<pfFormula>,<baseEvent1>,<baseEvent2>, ... ,<baseEventn>):
This derived type defines a new event whose value is computed from several native
events using a postfix (reverse polish notation) formula. Its value is the result of
processing the postfix formula. The 'pfFormula' is of the form 'N0|N1|N2|5|*|+|-|'
where the '|' acts as a token separator and the tokens N0, N1, and N2 are place
holders that represent baseEvent0, baseEvent1, and baseEvent2 respectively.

DERIVED_INFIX (<ifFormula>,<baseEvent1>,<baseEvent2>, ... ,<baseEventn>):
This derived type defines a new event whose value is computed from several native
events using an infix (algebraic notation) formula. Its value is the result of
processing the infix formula. The 'ifFormula' is of the form 'N0-(N1+(N2*5))' where
the tokens N0, N1, and N2 are place holders that represent baseEvent0, baseEvent1, and
baseEvent2 respectively.
Example:
In the following example, the events PAPI_SP_OPS, USER_SP_OPS, and ALIAS_SP_OPS will all
measure the same events and return the same value. They just demonstrate different ways to
use the PRESET and EVENT event definition commands.

· # The following lines define pmu names that all share the following events
· CPU nhm
· CPU nhm-ex
· # Events which should be defined for either of the above pmu types
· PRESET,PAPI_TOT_CYC,NOT_DERIVED,UNHALTED_CORE_CYCLES
· PRESET,PAPI_REF_CYC,NOT_DERIVED,UNHALTED_REFERENCE_CYCLES
· PRESET,PAPI_SP_OPS,DERIVED_POSTFIX,N0|N1|3|*|+|,FP_COMP_OPS_EXE:SSE_SINGLE_PRECISION,FP_COMP_OPS_EXE:SSE_FP_PACKED,NOTE,'Using
a postfix formula'
· EVENT,USER_SP_OPS,DERIVED_INFIX,N0+(N1*3),FP_COMP_OPS_EXE:SSE_SINGLE_PRECISION,FP_COMP_OPS_EXE:SSE_FP_PACKED,NOTE,'Using
the same formula in infix format'
· EVENT,ALIAS_SP_OPS,NOT_DERIVED,PAPI_SP_OPS,LDESC,'Alias for preset event PAPI_SP_OPS'
· # End of event definitions for above pmu names and start of a section for a new pmu
name.
· CPU snb

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