man PAPI_derived_event_files (1): 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.