On Tue, Aug 09, 2005 at 03:19:58PM -0700, Martin J. Bligh wrote: > --On Tuesday, August 09, 2005 15:03:32 -0700 "Siddha, Suresh B" <[EMAIL > PROTECTED]> wrote: > > > On Fri, Aug 05, 2005 at 04:29:45PM -0700, Darren Hart wrote: > >> I have some concerns as to the intent vs. actual implementation of > >> SD_BALANCE_FORK and the sched_balance_fork() routine. > > > > Intent and implementation match. Problem is with the intent ;-) > > > > This has the intent info. > > > > http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=147cbb4bbe991452698f0772d8292f22825710ba > > > > To solve these issues, we need to make the sched domain and its parameters > > CMP aware. And dynamically we need to adjust these parameters based > > on the system properties. > > Can you explain the purpose of doing balance on both fork and exec? > The reason we did it at exec time is that it's much cheaper to do > than at fork - you have very, very little state to deal with. The vast > majority of things that fork will exec immediately thereafter. > > Balance on clone make some sort of sense, since you know they're not > going to exec afterwards. We've thrashed through this many times before > and decided that unless there was an explicit hint from userspace, > balance on fork was not a good thing to do in the general case. Not only > based on a large range of testing, but also previous experience from other > Unix's. What new data came forth to change this?
I agree with you. I will let Nick(the author) have a take at this. > > We can choose the leastly loaded CPU in the home node and we can let the > > load balance to move it to other nodes if there is an imbalance. > > Is that what it's actually doing now? That's not what Nick told me at > Kernel Summit, but is the correct thing to do for clone, I think. We don't do it today. But I would like to see that. thanks, suresh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
