On Sat, Sep 01, 2012 at 01:47:52PM +0100, Jonathan Tripathy wrote: > On 31/08/2012 13:41, Jonathan Tripathy wrote: > > > > > >On 31.08.2012 13:36, Jonathan Tripathy wrote: > >>On 31.08.2012 04:47, James Harper wrote: > >>>>Hi Kent, > >>>> > >>>>I'm going to try and reproduce it myself as well. I just > >>>>used IOMeter in a > >>>>Windows DomU with 30 workers, each having an io depth of 256. A *very* > >>>>heavy workload indeed, but my point was to see if I could > >>>>break something. > >>>>Unless the issue is specific to windows causing problems > >>>>(NTFS or whatever), > >>>>I'm guessing running fio with 30 jobs and an iodepth of 256 > >>>>would probably > >>>>produce a similar load. > >>>> > >>>>BTW, do you have access to a Xen node for testing? > >>>> > >>> > >>>Does the problem resolve itself after you shut down the windows DomU? > >>>Or only when you reboot the whole Dom0? > >>> > >> > >>Hi There, > >> > >>I managed to reproduce this again. I have to reboot the entire Dom0 > >>(the physical server) for it to work properly again. > >> > >>James, are you able to reproduce this? Kent, are there any other > >>tests/debug output you need from me? > >> > > > >BTW, I was using IOMeter's 'default' Access Specification with the > >following modifications: 100% random, 66% read, 33% write, and a > >2kB size. My bcache is formatted for 512bytes. > >-- > > > Kent, is there any debug output of some sort I could switch on and > help you figure out what's going on? If needs be, I can give you > access to my setup here where you can run these tests yourself, if > you're not keen installing Xen on your end :) Shell access would probably be fastest, I suppose... One thing that comes to mind is perhaps the load from background writeback is slowing things down. Two things you can do: set writeback_percent to 10, that'll enable a pd controller so it's not going full blast benchmark it with writeback_running set to 0 - that disables background writeback completely. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
