A framework for virtually transparent monitoring of parallel programs

This paper describes an architectural framework for virtually transparent monitoring of massively-parallel computers, which combines the principle of permanent probe monitoring with generic architectural models of the monitor, and the target parallel system. A virtually transparent monitor is one in which probe effects — namely, those effects which cause a monitored program to behave differently from the same, but unmonitored one — are effectively masked at the programming level. Permanent probe monitoring is a technique for realising virtual transparency, by allowing the software monitoring probes to remain permanently active within the target parallel system. The generic monitoring architecture introduced in the paper encompasses the description of a wide range of systems ranging from simple centralised monitors to highly-distributed ones. The framework has been validated and evaluated through the experimental realisation of a message communication monitor (Monitorix) in which the target system is a token-ring message router (Routix) for a transputer-based multiprocessor. Experimental results have shown the system to be reasonably efficient