Messages in this thread | | | Date | Tue, 10 Apr 2012 19:44:44 +0200 | From | Xose Vazquez Perez <> | Subject | Re: [RFC PATCH] block: Change default IO scheduler to deadline except SATA |
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Vivek Goyal wrote:
> I am wondering if CFQ as default scheduler is still the right choice. CFQ > generally works well on slow rotational media (SATA?). But often > underperforms on faster storage (storage arrays, PCIE SSDs, virtualized > disk in linux guests etc). People often put logic in user space to tune their > systems and change IO scheduler to deadline to get better performance on > faster storage. > > Though there is not one good answer for all kind of storage and for all > kind of workloads, I am wondering if we can provide a better default and > that is change default IO scheduler to "deadline" except SATA. > > One can argue that some SAS disks can be slow too and benefit from CFQ. Yes, > but default IO scheduler choice is not perfect anyway. It just tries to > cater to a wide variety of use cases out of the box. > > So I am throwing this patch out see if it flies. Personally, I think it > might turn out to be a more reasonable default.
done time ago for dasd devices.
chuchi:~/curre/linux-2.6 $ grep -ri deadline drivers/s390/block/* drivers/s390/block/dasd.c: rc = elevator_init(block->request_queue, "deadline"); drivers/s390/block/Kconfig: select IOSCHED_DEADLINE
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