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SubjectRe: [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


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