[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Advanced questions
On Tue, 2003-11-11 at 15:25, Tvrtko A. Uršulin wrote: > Hello all, > > As I have reported earlier, everything works for me now! > > Therefore :), it is time for some more advanced questions: > > Is it possible to have more IP addresses per virtual domain? > Can a virtual domain reconfigure it's IP address? > > What kind of CPU time control is possible (or planned)? To be more precise, > how can one stop one domain to hog the cpu? (some kind of minimum guaranteded > CPU time setting?) Is there a description for xi_sched* helpers? the current scheduler is a weighted proportional fair scheduler. The scheduler is called BVT (Borrowed Virtual Time) and is described in this paper: http://citeseer.nj.nec.com/duda99borrowedvirtualtime.html. by default all domains have the same weight and should therefore share the CPU equally if they all need the CPU. xi_sched_domain allows you to change the weight of a domain. the first parameter is the domid, the second is the _inverse_ of the weight. For an explanation of the other parameters I'd suggest to read the paper. Essentially, they control the wake-up latency of a blocking domain. xi_sched_global sets a global parameter for the scheduler called context switch allowance. The default value is sensible and you shouldn't need to change it. Be aware that the xi_sched_* and the corresponding hypercalls do not do any range checking and allow you to shoot yourself in the foot. I guess this should be fixed :) To answer your other questions more directly: if you don't assign weights in a very skewed way one domain should not be able to hog the CPU. You can "guarantee" shares of CPU if you control the weights and the sum of weights carefully. there are vague plans to also provide a scheduler which gives absolute guarantees, rather than weighted proportional fairness. But that is not yet very high on the list but should be reasonably straight forward. > What happens if user inside virtual domain issues a reboot? (nothing eg. > stuck > - if my testing is correct). IMHO, it would be good if user could reboot. > > If I understand the documentation correctly, the memory size given with > xi_create is minimum guaranteed? Guest can grow beyond that, and under that > limit? There is a mention about absolute maximum limit. How is this set? My understanding is that all memory a domains gets is guaranteed. a domain might _voluntarily_ relinguish some of its memory (e.g., using the balloon driver) but will get it back when it asks for it. This also means that xen can't allocate the memory it gets back from a domain permanently and guaranteed to another domain. Rolf > > Many thanks for all the help! > > Best regards, > Tvrtko A. Ursulin ------------------------------------------------------- This SF.Net email sponsored by: ApacheCon 2003, 16-19 November in Las Vegas. Learn firsthand the latest developments in Apache, PHP, Perl, XML, Java, MySQL, WebDAV, and more! http://www.apachecon.com/ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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