As microarchitectural and system complexity grows, comprehending system behavior becomes increasingly difficult, and often requires obtaining and sifting through voluminous event traces or coordinating results from multiple, nonlocalized sources. Owl is a proposed framework that overcomes limitations faced by traditional performance counters and monitoring facilities in dealing with such complexity by pervasively deploying programmable monitoring elements throughout a system. The design exploits reconfigurable or programmable logic to realize hardware monitors located at event sources, such as memory buses. These monitors run and writeback results autonomously with respect to the CPU, mitigating the system impact of interrupt-driven monitoring or the need to communicate irrelevant events to higher levels of the system. The monitors are designed to snoop any kind of system transaction, e.g., within the core, on a bus, across the wire, or within I/O devices. Categories and Subject Desc...
Martin Schulz, Brian S. White, Sally A. McKee, Hsi