One example embodiment is a method that simulates a sampling period of an application to collect execution counts of basic blocks and compute cycles per instruction (CPI) data. A non-sampling period of the application is simulated to collect execution counts of basic blocks, and a comparison of the execution counts collected during the sampling period is performed to the execution counts collected during the non-sampling period. Based on the comparison, a determination is made whether to estimate CPI for the basic blocks during the non-sampling period using the CPI data collected during the sampling period.