On Tue, Feb 17, 2009 at 2:02 PM, Mark Perry <[email protected]> wrote:
> Rob van der Heij wrote: >> I only looked at cpuplugd for dealing with virtual processors, and my >> comments about waste of energy applied to that. > > Your energy or the System z's ? > > cpuplugd and z/VM 5.4 work nicely together taking idle processors out of > the dispatcher list, and working with the Guest's SHARE. Why would idle virtual processors be in the dispatch list? I agree that when Linux does not have work to use more than one engine, it should not involve all virtual processors to do that little work. Processor affinity does not really apply to Linux on z/VM. It could improve scalability if it would leave others alone. Whether you give an application multiple virtual CPU's is based on capacity planning and business justification. To me that does not imply that when the application is less active during part of the day, it should be put in front of the others to do its little bit of work. The reported "good results" seem to build on different performance criteria than I would apply to real world workload. Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
