Re: [PATCH 3/4] add ksm kernel shared memory driver

Avi Kivity
2008-11-11T22:49:19Z

Izik Eidus wrote:
>> Any benchmarks on the runtime cost of having KSM running?
>>
>
> This one is problematic, ksm can take anything from 0% to 100% cpu
> its all depend on how fast you run it.
> it have 3 parameters:
> number of pages to scan before it go to sleep
> maximum number of pages to merge while we scanning the above pages
> (merging is expensive)
> time to sleep (when runing from userspace using /dev/ksm, we actually
> do it there (userspace)

The scan process priority also has its effect. One strategy would be to
run it at idle priority as long as you have enough free memory, and
increase the priority as memory starts depleting.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.