Performance monitoring circuitry, method and computer program

A method for monitoring performance of software executing on processing circuitry;

• the method comprising:
• configuring a plurality of event counters based on counter configuration information, the counter configuration information comprising event type assignment information indicative of which types of event are assigned to be monitored by the event counters;
• using the plurality of event counters, maintaining respective event count values based on monitoring of events during processing of the software by the processing circuitry;
• and
• for a given event counter within at least a subset of the event counters, performing a chained-counter operation for at least one setting of the counter configuration information, the given event counter maintaining a given event count value;
• the chained-counter operation comprising incrementing the given event count value by an increment value determined based on a logical combination of a first event status indication indicative of status of a first event type assigned by the counter configuration information to be monitored by the given event counter and a second event status indication indicative of status of
• a second event type assigned by the counter configuration information to be monitored by a further event counter.

A computer program comprising instructions which, when executed by a host data processing apparatus, control the host data processing apparatus to provide an instruction execution environment for executing target program code, the computer program comprising:

• event counting program logic to maintain a plurality of event count values based on monitoring of events during simulated processing of the target program code by target processing circuitry;
• and
• control program logic to configure the event counting program logic based on counter configuration information, the counter configuration information comprising event type assignment information indicative of which types of event are assigned to be monitored using the plurality of event count values by the event counting program logic;
• wherein:
• for at least a subset of the event count values, for at least one setting of the counter configuration information the event counting program logic is configured to support a chained-counter operation for maintaining a given event count value in the subset;
• the chained-counter operation comprising incrementing the given event count value by an increment value determined based on a logical combination of a first event status indication indicative of status of a first event type assigned by the counter configuration information to be monitored using the given event count value and a second event status indication indicative of status of a second event type assigned by the counter configuration information to be monitored by a further event counter.