We've found that guests are pretty resilient to "timeouts", though its quite possible they've never really exceeded 200 milliseconds.
> -----Original Message----- > From: Luck, Tony [mailto:[EMAIL PROTECTED] > Sent: Friday, September 09, 2005 4:36 PM > To: Magenheimer, Dan (HP Labs Fort Collins); Christoph > Lameter; [email protected] > Subject: RE: [RFC] timer_interrupt: Avoid device timeouts by > freezing time if system froze > > >I am aware of at least two ia64 virtualization systems > >that rely on the existing behavior to compensate for > >the fact that one guest linux may be inactive while another > >is active. This isn't to say that another solution > >couldn't be found, but just turning off the existing > >behavior doesn't seem like a good alternative. > > There must be some minimum frequency at which a hypervisor > allows a guest to run in order for it to operate normally > [e.g. a guest that gets no cpu time for several seconds at > a stretch will experience network time-outs with external > systems that it is unable to supply with "keep-alive" packets]. > > I'm not sure what that minimum frequency is, but I expect that > it may be contrained by some of the shorter TCP timeouts. I > think that there is one around the 200 milli-second mark. > > So possibly a hypervisor that starves a guest for long enough > to trigger Christoph's patch has other problems than just > keeping time correct in the guest. > > -Tony > - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
