On Wed, Jul 29, 2009 at 6:31 PM, Mulyadi Santosa <[email protected]>wrote:
> Hi Cheetan... > > Thanks for your fast reply... > > On Wed, Jul 29, 2009 at 6:15 PM, Chetan Nanda<[email protected]> > wrote: > > > > > > On Wed, Jul 29, 2009 at 4:15 PM, Mulyadi Santosa < > [email protected]> > > 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. > > Is it what I read as so called virtual clock? 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. > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer > blog: the-hydra.blogspot.com > Thanks, Chetan Nanda
