Ex-mon: An architectural framework for dynamic program monitoring on multicore processors

Abstract

For modern software systems that operate in complex execution environments, reliability is key. The ability for observing the internal states of an executing program can facilitate a spectrumof programexecutionmonitors to en- hance software reliability; and modern multicore processors provide the computing power needed by such monitors. This paper presents Ex-Mon, novel hardware and software supports that enable efficient and flexible dynamic program execution monitoring. In Ex-Mon, a hardware- based extraction logic that can be configured dynamically by the monitoring software, is integrated onto each pro- cessor core. The extraction logic forwards events that are of interests to themonitoring software for correctness ver- ification. We evaluate the effectiveness and efficiency of the proposed system by using it to detectmemory-bugs in the SPEC2000 benchmark suite. The experiments show that performance overhead of Ex-Mon is 15% on average and 41.4%in the worst case. The bandwidth requirement of the proposed systemis below10 bits per cycle,which is acceptable considering the bandwidth capacity of today’s state-of-the-art on-chip interconnect network.