Date: Tue, 30 Oct 2012 18:33:27 -0500 (CDT) From: Steven Nikkel <steven_nikkel@ertyu.org> To: Andriy Gapon <avg@FreeBSD.org> Cc: freebsd-stable@FreeBSD.org Subject: Re: CPU Competition Issue Message-ID: <M.O.0.1210301826490.70211@ertyu.org> In-Reply-To: <508F9671.3060501@FreeBSD.org> References: <M.O.0.1210292022200.70211@ertyu.org> <508F9671.3060501@FreeBSD.org>
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On Tue, 30 Oct 2012, Andriy Gapon wrote: >> I'm running a long duration CPU-centric process that will gobble up all >> available CPU time. I have it set to run at nice +20. While it's running I've >> noticed other processes have a hard time getting CPU time and run their >> activites very slowly. The processes I've noticed issues with are IO involved, >> but they don't appear to be IO blocked as they run dramatically faster and use >> much more CPU time when the CPU intensive process is not running. I haven't >> noticed issues with other processes, but I haven't been looking. If I push my >> CPU intensive process into idle priority 1, all the other processes return to >> their normal behaviour as if it's not running. >> >> This seems to be a specific behaviour on this one machine running 9.0-RELEASE-p4 >> on an Atom 330 dual core. I've tried with and without hyperthreading enabled >> with no noticeable change in behaviour. > > Can you try with lower nice value, like +10? > You want a fix from r228718. AFAIR, it is not in 9.0. > They seem to share in a much more reasonable manor after assigning the process to +10 instead of +20, which sounds like the fix you mentioned. The process hits priorities in the 120s when its competing. I think I'll continue with idle priority as that obtains the sharing behaviour I'm after.
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