最差情况执行时间估计值的二次修正方法

摘要

针对基于隐藏路径枚举技术的最差情况执行时间分析方法在估计含非正交多重嵌套循环(或递归)程序的最差情况执行时间时往往过于保守，估计值过高的问题，本文提出了一种最差情况执行时间估计值的二次修正方法。该方法将通常采用的内层循环(或递归)语句的局部循环上界修正为相对于外层循环(或递归)语句全局执行次数的平均执行次数，从而实现了对过高估计值的修正。实验结果表明，该方法即能够有效降低过高的估计值，又能够保证修正结果是安全的。%The worst-case execution time ( WCET) analysis method based on implicit path enumeration tech-nique ( IPET) is often too conservative. Therefore,when using it to estimate the WCET of the programs which include nonorthogonal multiple nested loops ( or recursions) ,the WCET is overrated usually. Aim at this prob-lem,this paper proposes a twice correction method for estimated value of WCET. The method uses the global average execution counts instead of the local maximum execution counts as the loop bound of the inner loop ( or recursion) statement. So the method corrects the excessive estimated value. Experimental results show that the method can effectively reduce the estimated value that is too high,and the result is corrected to ensure safety.