Messages in this thread | | | Date | Wed, 9 Sep 2009 21:48:52 +0200 | From | Pavel Machek <> | Subject | Re: [tip:sched/core] sched: Turn off child_runs_first |
| |
Hi!
> > > It hurts 'optimal' make -j<NR_CPUS> workloads as make jobs > > > get preempted by child tasks, reducing parallelism. > > > > Wasn't one of the reasons why we historically did child_runs_first > > was so that for fork/exit workloads, the child has a chance to > > exec the new process? If the parent runs first, then more pages > > will probably need to be COW'ed. > > That kind of workload should be using vfork() anyway, and be even > faster because it can avoid the fork overhead, right?
Well.. one should not have to update userspace to keep performance.... and vfork is extremely ugly interface.
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
| |