No sorry, I haven't any performance data with noop. I even don't have had a crash. BUT I've experienced serve I/O degradation with noop. Once I've written a big chunk of data (e.g. a simple rsync -av /usr /opt) with noop it works for a while and after a few seconds I saw heavy writes which made the VM virtually unusable. As far as I remember it was kjournald which cases the writes.
I've written a mail to the list some months ago with some benchmarks: http://article.gmane.org/gmane.comp.emulators.kvm.devel/41112/match=benchmark There're some I/O benchmarks in there. You can't get the graphs currently since tauceti.net is offline until monday. I haven't tested noop in these benchmarks because of the problems mentioned above. But it compares deadline and cfq a little bit on a HP DL 380 G6 server. Robert On 01/21/10 22:08, Thomas Beinicke wrote: > On Thursday 21 January 2010 21:08:38 RW wrote: >> Some months ago I also thought elevator=noop should be a good idea. >> But it isn't. It works good as long as you only do short IO requests. >> Try using deadline in host and guest. >> >> Robert > > @Robert: I've been using noop on all of my KVMs and didn't have any problems > so far, never had any crash too. > Do you have any performance data or comparisons between noop and deadline io > schedulers? > > Cheers, > > Thomas > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
