Re: Understanding I/O behaviour

[Martin Knoblauch <knobi@knobisoft.de>]

Brice Figureau wrote:

>> CFQ gives less (about 10-15%) throughput except for the kernel
>> with the
>> cfs cpu scheduler, where CFQ is on par with the other IO
>> schedulers.
>>
>
>Please have a look to kernel bug #7372:
>http://bugzilla.kernel.org/show_bug.cgi?id=7372
>
>It seems I encountered the almost same issue.
>
>The fix on my side, beside running 2.6.17 (which was working fine
>for me) was to:
>1) have /proc/sys/vm/vfs_cache_pressure=1
>2) have /proc/sys/vm/dirty_ratio=1 and 
> /proc/sys/vm/dirty_background_ratio=1
>3) have /proc/sys/vm/swappiness=2
>4) run Peter Zijlstra: per dirty device throttling patch on the
> top of 2.6.21.5:
>http://www.ussg.iu.edu/hypermail/linux/kernel/0706.1/2776.html

Brice,

 any of them sufficient, or all together nedded? Just to avoid
confusion.

Cheers
Martin


------------------------------------------------------
Martin Knoblauch
email: k n o b i AT knobisoft DOT de
www:   http://www.knobisoft.de