On 28 December 2017 at 00:39, Duncan <1i5t5.duncan@xxxxxxx> wrote: > > AFAIK, ionice only works for some IO schedulers, not all. It does work > with the default CFQ scheduler, but I don't /believe/ it works with > deadline, certainly not with noop, and I'd /guess/ it doesn't work with > block-multiqueue (and thus not with bfq or kyber) at all, tho it's > possible it does in the latest kernels, since multi-queue is targeted to > eventually replace, at least as default, the older single-queue options. > > So which scheduler are you using and are you on multi-queue or not? > Thank you. The install had defaulted to deadline. I have now switched it to CFQ, and the system is much more responsive/interactive now during a btrfs balance. I will test it when I next get a chance, to see if that has helped me. After reading about it: deadline: more likely to complete long sequential reads/writes and not switch tasks.Thus reducing the amount of seeking but impacting concurrent tasks. cfq: more likely to break up long sequential reads/writes to permit other tasks to do some work. Thus increasing the amount of seeking but helping concurrent tasks. This would explain why "cfq" is best for me. I have not yet looked at "multi-queue". -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
