[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Questions about the use of idle_vcpu[]
On Mon, Jan 18, 2016 at 11:00 AM, Dario Faggioli <dario.faggioli@xxxxxxxxxx> wrote: >> It looks like credit2's behavior will probably prevent the processor >> from going into deeper power-saving states, and rtds' behavior might >> cause it to essentially busy-wait. >> > RTDS behavior is broken in many respect, including this, and in fact, > Meng and Tianyang are sending patches already to fix it (I'll let you > guys have my comments shortly :-P). > > Credit2, AFAICR, could also avoid _always_ re-setting the timer, but it > does need to do that at least a few times, even when idle is selected, > because of the dynamic load tracking mechanism it includes. In fact, > that is based on a 'decaying average', which in turns relies on > csched2_schedule() to run and update the statistics, even when the cpu > is idle. If we don't do that, the load tracking mechanism will never > see that the cpu (well, it's actually the runqueue) is idle, and the > load will never go down! :-/ I don't think that's true -- it looks like balance_load() will call __update_runq_load() on the "other" runqueue before considering it, and will also call __update_svc_load() on each vcpu before considering it. Shouldn't that suffice? -George _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |