Messages in this thread | | | Subject | Re: BFQ speed tests [was Re: [PATCH RFC - TAKE TWO - 00/12] New version of the BFQ I/O Scheduler] | From | Paolo Valente <> | Date | Wed, 4 Jun 2014 12:24:30 +0200 |
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Il giorno 04/giu/2014, alle ore 12:03, Pavel Machek <pavel@ucw.cz> ha scritto:
> Hi! > >> Should this attempt be useless as well, I will, if you do not mind, try by asking you more details about your system and reproducing your configuration as much as I can. >> > > Try making BFQ the default scheduler. That seems to break it for me, > when selected at runtime, it looks stable. > > Anyway, here are some speed tests. Background load: > > root@duo:/data/tmp# echo cfq > /sys/block/sda/queue/scheduler > root@duo:/data/tmp# echo 3 > /proc/sys/vm/drop_caches > root@duo:/data/tmp# cat /dev/zero > delme; cat /dev/zero > delme;cat > /dev/zero > delme;cat /dev/zero > delme;cat /dev/zero > delme;cat > /dev/zero > delme > > (Machine was running out of disk space.) > > (I alternate between cfq and bfq). > > Benchmark. I chose git describe because it is part of kernel build > sometimes .. and I actually wait for that. > > pavel@duo:/data/l/linux-good$ time git describe > warning: refname 'HEAD' is ambiguous. > v3.15-rc8-144-g405dedd > > Unfortunately, results are not too good for BFQ. (Can you replicate > the results?) > > # BFQ > 10.24user 1.62system 467.02 (7m47.028s) elapsed 2.54%CPU > # CFQ > 8.55user 1.26system 69.57 (1m9.577s) elapsed 14.11%CPU > # BFQ > 11.70user 3.18system 1491.59 (24m51.599s) elapsed 0.99%CPU > # CFQ, no background load > 8.51user 0.75system 30.99 (0m30.994s) elapsed 29.91%CPU > # CFQ > 8.70user 1.36system 74.72 (1m14.720s) elapsed 13.48%CPU >
Definitely bad, we are about to repeat the test …
Thanks, Paolo
> Pavel > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-- Paolo Valente Algogroup Dipartimento di Fisica, Informatica e Matematica Via Campi, 213/B 41125 Modena - Italy homepage: http://algogroup.unimore.it/people/paolo/
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