On 05/24/2017 12:32 PM, Martin Kletzander wrote: > On Tue, May 23, 2017 at 05:29:52PM +0200, Peter Krempa wrote: >> On Tue, May 23, 2017 at 17:19:53 +0200, Martin Kletzander wrote: >>> On Tue, May 23, 2017 at 05:07:40PM +0200, Michal Privoznik wrote: >>> > On 05/23/2017 04:35 PM, Martin Kletzander wrote: >>> > > On Tue, May 23, 2017 at 04:23:30PM +0200, Peter Krempa wrote: >> >> [...] >> >>> > > > + * Note that this API is prone to exceeding maximum RPC if >>> querying >>> > > > too many VMs >>> > > > + * with lots of statistics. It's suggested to query in batches of >>> > > > 10VMs, which >>> > > > + * should be good enough for VMs with 3000 disks + networks. >>> > > > + * >>> > > >>> > > Coming to think about it... Why don't we just batch this >>> ourselves under >>> > > the hood and just return the merged result? >>> > >>> > Because: >>> > >>> > https://www.redhat.com/archives/libvir-list/2017-May/msg00088.html >>> > >>> >>> Not on the RPC level, the API would just be syntax sugar to >>> virDomainListGetStats() if a flag was passed >>> (e.g. >>> VIR_DOMAIN_GET_ALL_STATS_I_DONT_REALLY_CARE_IF_THIS_IS_DONE_IN_ONE_LIBVIRT_CALL) >>> >> >> Also compared to a full fragmentation of the returned data, this would >> result into a worst-case-scenario memory usage of MAX_SIZE * >> NVMS_QUERIED_IN_ORIGINAL_CALL, when compared to an unbounded memory use >> of the full fragmentation approach. > > If I get what you are saying, then the same would happen if the mgmt app > (or client) implemented it themselves. We would basically just provide > the guessing logic. That's quite exact. I mean the word 'guessing'. We can't really provide reliable way of dealing with what you're suggesting (unless we cut the limit really small) nor we can guarantee atomicity. Therefore I think it would be a waste of time to work on this. Yes, it can be done, but the benefits are pretty small IMO. Michal -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
