Abstract: The invention is directed to instrumenting object code of an application and/or an operating system on a target machine so that execution trace data can be generated, collected, and subsequently analyzed for various purposes, such as debugging and performance. Automatic instrumentation may be performed on an application's object code before, during or after linking. A target machine's operating system's object code can be manually or automatically instrumented. By identifying address space switches and thread switches in the operating system's object code, instrumented code can be inserted at locations that enable the execution trace data to be generated. The instrumentation of the operating system and application can enable visibility of total system behavior by enabling generation of trace information sufficient to reconstruct address space switches and context switches.

Abstract: Methods, apparatus, and articles of manufacture to virtualize performance counters are disclosed. An example method includes scheduling a virtual machine on a processor, incrementing a virtual performance counter in response to an occurrence of a speculative event during direct execution of guest instructions by the virtual machine on the processor, and incrementing the virtual performance counter in response to an occurrence of the speculative event during execution of emulated instructions by a hypervisor on behalf of the virtual machine on the processor.