[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] Deferrable Timer
Kevin, Let me just try to use the deferrable timers as they are specified today. If I have trouble doing so, then we can discuss at that point. thanks, Dave Tian, Kevin wrote: >>From: Dave Winchell [mailto:dwinchell@xxxxxxxxxxxxxxx] >>Sent: 2008年7月18日 23:29 >> >>Vpt.c works in a similar fashion for its periodic timer. Other >>clocksources, >>e.g. pit, rtc, are layred on vpt.c with interface >>create_periodic_timer. >>I can imagine an option passed to create_periodic_timer signifying that >>a deferrable timer may be used. >> >> > >Agree. > > > >>Ideally, the deferrable timer would have an option where a set >>of allowable >>timeout values, rather than a range, could be provided. If it had this >>option, we could keep >>the timeouts on the integer*period time line. Otherwise I need to warp >>the comparator >>as discussed below. I anticipate that there may be some problems with >>warping. >> >> > >Not sure why this option is required. In any case, you just keep cmp >updated by integer*period which is just enough in timer fn and has >nothing to do with whether timer is deferred. Timers are always deferred >before and after, with only difference on the extent, especially when >you consider the point when guest gets chance to act on it. > > > > >>I realize that specifying a range gives you more options for combining >>timeouts. >>I don't mind trying to solve the warping problem. >> >> > >Yes, the purpose of the deferral is to reduce timer ticks, or else it >really make no sense. > > > >>One further option would be a deferrable timer with a range >>fallowed by >>a non-deferrable >>timer to get back on the integer*period timeline for interrupt >>delivery. >> >> > >What's the purpose then? current algorithm to find whether one >timer should be deferred is to find whether other timers may >expire in its tolerated future, regardless of whether next timer >is deferrable or not. Why do you care whether next one is >non-deferrable? > >Thanks, >Kevin > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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