On Thu, Apr 19, 2007 at 08:38:10AM +0200, Ingo Molnar wrote: > > * Andrew Morton <[EMAIL PROTECTED]> wrote: > > > > And yes, by fairly, I mean fairly among all threads as a base > > > resource class, because that's what Linux has always done > > > > Yes, there are potential compatibility problems. Example: a machine > > with 100 busy httpd processes and suddenly a big gzip starts up from > > console or cron. > > > > Under current kernels, that gzip will take ages and the httpds will > > take a 1% slowdown, which may well be exactly the behaviour which is > > desired. > > > > If we were to schedule by UID then the gzip suddenly gets 50% of the > > CPU and those httpd's all take a 50% hit, which could be quite > > serious. > > > > That's simple to fix via nicing, but people have to know to do that, > > and there will be a transition period where some disruption is > > possible. > > hmmmm. How about the following then: default to nice -10 for all > (SCHED_NORMAL) kernel threads and all root-owned tasks. Root _is_ > special: root already has disk space reserved to it, root has special > memory allocation allowances, etc. I dont see a reason why we couldnt by > default make all root tasks have nice -10. This would be instantly loved > by sysadmins i suspect ;-)
I have no problem with doing fancy new fairness classes and things. But considering that we _need_ to have per-thread fairness and that is also what the current scheduler has and what we need to do well for obvious reasons, the best path to take is to get per-thread scheduling up to a point where it is able to replace the current scheduler, then look at more complex things after that. - 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/
