On Wed, Jul 09, 2014 at 11:20:40PM -0700, Christoph Hellwig wrote: > On Thu, Jul 10, 2014 at 12:53:36AM +0000, Elliott, Robert (Server Storage) wrote: > > the problem still occurs - fio results in low or 0 IOPS, with perf top > > reporting unusual amounts of time spent in do_io_submit and io_submit. > > The diff between the two version doesn't show too much other possible > interesting commits, the most interesting being some minor block > updates. > > I guess we'll have to a manual bisect, I've pushed out a > scsi-mq.3-bisect-1 branch that is rebased to just before the merge of > the block tree, and a scsi-mq.3-bisect-2 branch that is just after > the merge of the block tree to get started. There is one possible concern that could be exacerbated by other changes in the system: if the application is running close to the bare minimum number of requests allocated in io_setup(), the per cpu reference counters will have a hard time batching things. It might be worth testing with an increased number of requests being allocated if this is the case. -ben -- "Thought is the essence of where you are now." -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
