Number of memory passes

In all our tests, we observed that the number of memory passes performed by z/VM® during the relocation process was eight.

See Test metrics for more information about memory passes . This is attributed to the memory access pattern of the test workload that accesses memory in a random pattern with a more or less constant rate over time, resulting in a more or less constant working set over time as well.

The observed number of eight memory passes confirms the statement made in the z/VM performance report (see Live Guest Relocation) that if an application is not making progress toward the quiesce threshold, or in other words, the amount of memory transferred with each memory pass does not decrease consistently, then z/VM will complete the live guest relocation in eight memory passes.