[Spice-devel] [Users] multiple concurrent spice consoles (was Ovirt + Spice + VDI)

[Itamar Heim]

On 09/14/2012 03:28 PM, John A. Sullivan III wrote:
...

>>> > >   Moreover, all instances in memory only take the space of
>>> > >one instance. Thus, we get deduplication and KSM almost for free.
>> >
>> >oVirt (RHEV) runs KSM only when the host memory gets fuller but I seem
>> >to remember that guys were able to have high 1000's of % of memory
>> >overcommit ratios
> I have heard rumors of high CPU utilization with KSM but we have not
> experimented enough with it ourselves to know.  Is that an issue?

ksm takes cpu, but servers today are loaded with cores, but memory is 
still the expensive part.
today we configure ksm to kick in only when memory is ~80%, which is 
when you'd usually be willing to pay the price of one of your cores 
spending some time on ksm, then the memory congestion on the host / 
losing memory overcommit.