On Mon, Nov 05, 2012 at 02:21:37PM +0200, Orit Wasserman wrote: > On 11/05/2012 02:30 AM, David Gibson wrote: > > On Fri, Nov 02, 2012 at 02:12:25PM +0200, Orit Wasserman wrote: > >> On 11/02/2012 05:10 AM, David Gibson wrote: > >>> Asking for some advice on the list. > >>> > >>> I have prorotype savevm and migration support ready for the pseries > >>> machine. They seem to work under simple circumstances (idle guest). > >>> To test them more extensively I've been attempting to perform live > >>> migrations (just over tcp->localhost) which the guest is active with > >>> something. In particular I've tried while using octave to do matrix > >>> multiply (so exercising the FP unit) and my colleague Alexey has tried > >>> during some video encoding. > > > >> As you are doing local migration one option is to setting the speed > >> higher than line speed , as we don't actually send the data, another > >> is to set high downtime. > > > > I'm not entirely sure what you mean by that. But I do have suspicions > > based on this and other factors that the default bandwidth it is > > limiting to is horribly, horribly low. > > > >>> However, in each of these cases, we've found that the migration only > >>> completes and the source instance only stops after the intensive > >>> workload has (just) completed. What I surmise is happening is that > >>> the workload is touching memory pages fast enough that the ram > >>> migration code is never getting below the threshold to complete the > >>> migration until the guest is idle again. > >>> > >> The workload you chose is really bad for live migration, as all the > >> guest does is dirtying his memory. > > > > Well, I realised that was true of the matrix multiply. For video > > encode though, the output data should be much, much smaller than the > > input, so I wouldn't expect it to be dirtying memory that fast. > > > >> I recommend looking for workload > >> that does some networking or disk IO. Vinod succeeded running > >> SwingBench and SLOB benchmarks that converged ok, I don't know if > >> they run on pseries, but similar workload should be ok(small > >> database/warehouse). We found out that SpecJbb on the other hand is > >> hard to converge. Web workload or video streaming also do the > >> trick. > > > > Hrm. As something really simple and stupid, I did try migrationg an > > ls -lR /, but even that didn't converge :/. > That is strange, it should converge even with the defaults, > Any special about your storage setup ?
I didn't think so. Do you mean host or guest storage setup? -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson