I have try the BFQ patch outside of the kernel mainline, it works well.
Maybe you would like to see:
http://algo.ing.unimo.it/people/paolo/disk_sched/
Also there is a 15-minute demo of the performance of BFQ:
http://youtu.be/J-e7LnJblm8
2013/3/10 Volker Armin Hemmann <[email protected]>
> Am 09.03.2013 19:15, schrieb Florian Philipp:
> > Hi list!
> >
> > Whenever I do sequential IO for a long stretch of time (e.g. md5summing
> > 40 GB), I'm experiencing high load (ca. 6 on a 4 CPU system) and
> > temporary freezes of most applications. For example, switching between
> > tabs in konsole sometimes takes more than 2 seconds.
> >
> > When doing this on an ext4 filesystem, the load seems to result from
> > khugepaged and kswapd0 as well as some kworkers.
> >
> > I think I've had similar issues with NFS over wifi but I cannot test
> > this now.
> >
> > Today I copied 60GB from my hard disk to an USB disk formatted with
> > NTFS, issuing the copy command from KDE's dolphin. The freezes became so
> > long it was impossible to work and then X11 locked up and had to be
> killed.
> >
> > I tried using a preemptive kernel but that didn't seem to help. blkio
> > and cpu cgroups didn't help either. Ionice seems to be the only solution
> > but while I'm okay with that, my dad won't be. Can anyone tell me what
> > is causing this behavior?
> >
> > Throughput is good, by the way. That's why I don't suspect a driver
> issue.
> >
> > Thanks in advance!
> > Florian Philipp
> >
> congratulation. You hit 'the bug'. Been around for ages, but for magical
> reasons kernel dev are unable to see or unable to do something about it.
> If you are using a vanilla kernel, posting on lkml might be the right
> thing to do.
>
>
--
Best regards!
------------------------------------------------
Yu-yu Lin(林育宇)
The Guangdong Key Laboratory of Information Security Technology (IST),
School of Information Science and Technology,
Sun Yat-sen (Zhongshan) University (中山大学),
Guangzhou,P.R.China.
Email: [email protected]
------------------------------------------------ <[email protected]>
