Robert Watson wrote: > In the mean time, it sounds like the sysctl does need to be > reimplemented or removed, but one question is how far to take it -- > caches are shared to varying degrees at varying levels of the topology. > However, I believe the recommendation has generally moved to disabling > hyperthreading using the BIOS, as that uses the vendor's notion of > hyperthreading. The idea of changing the setting at run-time is > currently untenable because we don't have the OS infrastructure to take > CPUs out of service, although growing it would be useful in order to > support virtual machine dynamic CPU reconfiguration. Well, as far as I know, what SCHED_4BSD does is simply stopping scheduling threads to the logical core(s). One doesn't need infrastructure to take CPU off-line for doing the same in SCHED_ULE. Unfortunately access to BIOS is not always an option and also some BIOSes don't even provide a feature to turn HTT off. -MaximReceived on Mon Feb 23 2009 - 17:39:57 UTC
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