Re: [fedora-virt] F12 and ksm/ksmtuned: info required...
On 11/24/2009 08:00 PM, Dan Kenigsberg wrote:
On Tue, Nov 24, 2009 at 06:43:42PM +0530, kashyap chamarthy wrote:
> On 11/24/2009 05:31 PM, Gianluca Cecchi wrote:
>> On Tue, Nov 24, 2009 at 12:50 PM, Dan Kenigsberg<danken(a)redhat.com>
wrote:
>>>
>>> yes, the purpose of ksmtuned is to tune ksm parameters, or stop it
>>> altogether if it is not needed. In case your two virtual machines
>>> required less than available memeory, ksm is not used. If ksmtune senses
>>> that memory stress has risen, it fires up ksm again.
>>>
>>> I don't think this is written anywhere but in the code.. We probably
>>> should add something to the "User experience" section to that
feature page.
>>> How about:
>>>
>>> Fedora's kvm comes with 2 services controlling the behavior of ksm. One,
>>> simply called ksm, is just a nice means to start and stop ksm's kernel
>>> thread. The other, called ksmtuned, controls the first service and tunes
>>> its parameters according to the memory stress that is generated by KVM
>>> virtual machines.
>>>
>>
>> It sounds good; I would only add something like this:
>>
>> "In case of need, e.g. in minor load situations, ksmtuned can also
>> stop ksm service at all.
>> Later, if ksmtuned senses that memory stress has risen, it will fire
>> up ksm again."
>>
>> So that one knows that to monitor the status of ksm is not a good idea
>> in general.....
>> Any log configurable to see/trace ksmtuned decisions (start ksm, stop
>> ksm, increase pages...)?
>
> yes, configuratble log/trace info for ksm/ksmtuned would be useful.
>
> I see this for configuration stuff - /etc/ksmtuned.conf
>
> /kashyap
You'd have to apply the following patch to /usr/sbin/ksmtuned for it to
easily log into /var/log/ksmtuned. You'd have to add two lines to
/etc/ksmtuned.conf for this to actually work.
thanks a lot. will try it.
/kashyap
Regards,
Dan.