Date: Sat, 20 Jun 2015 11:20:38 -0700 From: Dieter BSD <dieterbsd@gmail.com> To: freebsd-hackers@freebsd.org Subject: Re: Realtime process CPU starvation Message-ID: <CAA3ZYrDXmMXk1ZuP0oGd_6G%2BvKTXtfA6mPAsx_spgojHMnE81Q@mail.gmail.com>
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For those who care, I'm running kern.sched.name: ULE My (feeble) understanding is that the scheduler mostly looks at cpu time, and processes doing i/o actually get a bump *up* in priority, since because of the way hardware worked in the late 1970s-early 1980s (PDP-11, VAX, ...) the i/o got useful work done while using very little cpu time. As a result, jobs that do a lot of i/o can receive more than their fair share of cpu time. And nice(1) (even rtprio and idprio) may not have much effect on jobs that are i/o bound. Some form of ionice is sorely needed.
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