Messages in this thread | | | Subject | Re: [PATCH RFC] block, bfq: set default slice_idle to zero for non-rotational devices | From | Holger Hoffstätte <> | Date | Thu, 1 Nov 2018 20:06:09 +0100 |
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On 11/01/18 18:43, Konstantin Khlebnikov wrote: > With default 8ms idle slice BFQ is up to 10 times slower than CFQ > for massive random read workloads for common SATA SSD. > > For now zero idle slice gives better out of box experience. > CFQ employs this since commit 41c0126b3f22 ("block: Make CFQ default > to IOPS mode on SSDs")
Well, that's interesting because 3 years ago I made the same suggestion and was told that BFQ's heuristics automagically make it not idle when rotational=0. Did you actually benchmark this? I just tried and don't get a noticeable performance difference with slice_idle=0 compared to deadline.
Discussion link: https://groups.google.com/forum/#!msg/bfq-iosched/iRMw2n3kYLY/6l9cIm3TBgAJ
curious..
Holger
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