The total Db2 CPU time per transaction, which consists of the Db2 class 2 CPU time plus  MSTR, DBM1, and IRLM CPU time per transaction for each migration scenario is shown in  Figure 5-6.  Db2 12 at function level V12R1M100 benefits from many Db2 12 internal optimizations that  are not available in older Db2 releases. At function level V12R1M500, Db2 shows more  performance benefits because GBP-dependent index objects also become eligible for fast  index traversal.  After rebinding with APREUSE(NONE), we observed minor access path changes in several  packages of the workload. However, Db2 accounting reports indicated similar getpage counts  per occurrence for the packages with changed access paths. Also, class 7 CPU time was  nearly identical for these packages. 170  IBM Db2 12 for z/OS Performance Topics Figure 5-6 Total Db2 CPU time per transaction