Re: [PATCH] block: BFQ default for single queue devices

Paolo Valente
2018-10-03T16:09:58Z

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Il mer 3 ott 2018, 18:02 Paolo Valente <paolo.valente@linaro.org> ha
scritto:

>
>
> > Il giorno 03 ott 2018, alle ore 17:54, Bart Van Assche <
> bvanassche@acm.org> ha scritto:
> >
> > On Wed, 2018-10-03 at 08:29 +0200, Paolo Valente wrote:
> >> [1] https://lkml.org/lkml/2017/2/21/791
> >> [2] http://algo.ing.unimo.it/people/paolo/disk_sched/results.php
> >> [3] https://lwn.net/Articles/763603/
> >
> > From [2]: "BFQ loses about 18% with only random readers, because the
> number
> > of IOPS becomes so high that the execution time and parallel efficiency
> of
> > the schedulers becomes relevant." Since the number of I/O patterns for
> which
> > results are available on [2] is limited and since the number of devices
> for
> > which test results are available on [2] is limited (e.g. RAID is
> missing),
> > there might be other cases in which configuring BFQ as the default would
> > introduce a regression.
> >
>
> From [3]: none with throttling loses 80% of the throughput when used
> to control I/O.
>

Of course, the same happens with mq-deadline plus throttling, sorry.

Paolo

>
>

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