On Tuesday, 03/08/2011 at 06:14 EST, "Gary M. Dennis" <gary.den...@mantissa.com> wrote: > If a z/VM guest partially or completely purges the TLB on a z10 or z196, is the > time required to quiesce CPs to coordinate the requested purge counted toward > total CPU time for the guest requesting the purge? If so does the guest > requesting the purge get tagged for all the CPU time required to coordinate > purge operations across all CPs for the z/VM or is the time apportioned by CP > to the specific guest active on each CP at the time the purge was requested? > > If the time isn?t counted toward CPU time for the guest requesting the purge, > how is that allocated?
When a guest causes that to happen, the the instruction that triggered it will be victimized by it as well. That means the instruction takes longer. Likewise, all the other CPUs within the LPAR will serialize and the instructions they are running take longer. So everyone else is penalized. The bottom line is that the CPU timer does not stop ticking just because the TLB has been purged. Instructions running in other LPARs are not affected since they don't access the same blocks of memory. Alan Altmark z/VM and Linux on System z Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott
