Il mer 3 ott 2018, 18:02 Paolo Valente [off-list ref] ha
scritto:

quoted

Il giorno 03 ott 2018, alle ore 17:54, Bart Van Assche <

bvanassche@acm.org> ha scritto:

quoted

On Wed, 2018-10-03 at 08:29 +0200, Paolo Valente wrote:

quoted

[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

quoted

of IOPS becomes so high that the execution time and parallel efficiency

of

quoted

the schedulers becomes relevant." Since the number of I/O patterns for

which

quoted

results are available on [2] is limited and since the number of devices

for

quoted

which test results are available on [2] is limited (e.g. RAID is

missing),

quoted

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