Processor performance metrics are assessed by monitoring probes constructed using instruction sequences. A probe comprising an instruction sequence is selected. The instruction sequence can be configured to measure at least one hardware metric. A first probe value is received. The first probe value can be based, at least in part, on the hardware metric. The first probe value can be determined from execution of the probe in a first execution environment. The probe can be executed a second time to determine a second probe value. The second probe value can be based, at least in part, on the hardware metric. The second probe value is determined in a second execution environment including at least one workload. The first probe value and the second probe value can be compared to produce a performance assessment of the second execution environment.