Re: [gentoo-user] Intel(R) C600 SAS Controller

[thegeezer <thegeezer@thegeezer.net>]

On 06/11/2014 01:41 PM, Stefan G. Weichinger wrote:
> Am 11.06.2014 13:52, schrieb thegeezer:
>
>> ok baffling.
>> sdc i already said would be slower but not this much slower
>> it certainly should not be slower than the lvm that sits on top of it!
>> i can't see anything in the cgroups that stands out, maybe someone else
>> can give a better voice to this.
>>
>> all i can think is there is other IO happening
>> in atop if you can highlight any line that begins LVM CPU or DSK and
>> paste it in to a reply - with no virtualmachines running and no dd or
>> anything.
>> then run a dd as before and highlight the lines in atop while it is
>> running (maybe increase count to 1000 to give yourself a chance) and
>> paste in here too
>
> I did a test with a sysresccd from 2013 (that is kernel 3.4.52 ... phew)
>
> Just booted, "vgchange -ay" and then the dd-test from LV to /dev/null
>
> -> with or without count=500 I get around 340-350 MB/s !
>
> So my kernel-config seems buggy or I should downgrade to something older?

I suspect that in your fully running system somethingelse(tm) is
stealing the activity.   can you start up with no services enabled and
do the test ?

> Aside from that I checked the firmware of the controller, it has the
> latest release.
>
> Stefan
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