On Wed, Jul 29, 2009 at 6:31 PM, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote:
Thanks,Hi Cheetan...
Thanks for your fast reply...
Is it what I read as so called virtual clock?
On Wed, Jul 29, 2009 at 6:15 PM, Chetan Nanda<chetannanda@xxxxxxxxx> wrote:
>
>
> On Wed, Jul 29, 2009 at 4:15 PM, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx>
> wrote:
>>
>> Hi all
>>
>> I've tried to check related scheduler code and I've got impression
>> that in CFS scheduler, dynamic priority level no longer determines
>> which process will be picked up by the scheduler. Instead, it is now
>> the waiting time that becomes the primary factor to watch...the longer
>> it waits, thus it is treated "more unfair"...then it will be picked
>> ASAP. Is this correct?
>
>
> AFAIK, this is correct
>
>>
>> If it is correct, then is it still useful to assign different nice
>> level to mark the importance of a process?
>
>
> Waiting time for different process are virtual time, I mean waiting time
> depends on priority of the process also.
> Waiting time of a process with higher priority will increase faster so that
> it get picked sooner.
Yes,
So, may I say that nice
level (thus also dynamic priority, since I check that in CFS, static
prio=dynamic prio..CMIIW) is somekind of weight factor of waiting
time?
For regular processes static priority is equal to dynamic priority. Yes waiting time depend on nice value of a process.
May refer Chapter 2nd of "Professional Linux® Kernel Architecture" it have a fair amount of implementation detail on CFS.
--
Chetan Nanda
