On Thu, Aug 27, 2009 at 04:02:41PM -0400, Martin K. Petersen wrote: > >>>>> "James" == James Bottomley <James.Bottomley@xxxxxxx> writes: > > >> This is not an option on a mirror system, and the performance > >> gain/lose is dependent on the round trip speed. If for every digest > >> error I have an error recovery cycle, delays, and stalls. Then no it > >> is not better. Not to mention some iscsi-targets that reset and the > >> all session must be re-established. > > James> Your suggestion of putting processes to sleep while I/O is > James> pending will degrade performance for everyone; that's not really > James> an acceptable tradeoff for improving one corner case. > [ changing pages in flight ] > > In my opinion ext[234] should simply be fixed. If there's a significant > performance hit on those filesystems we could make the wait conditional > on a block_device flag. I agree here. It is pretty trivial in the filesystem to wait for pages in flight, and it shouldn't be the job of the lower layers to double buffer 100% of the time. -chris -- 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
