Date: Wed, 07 Aug 2013 16:33:03 +0800 From: David Xu <davidxu@freebsd.org> To: dave@mischler.com Cc: freebsd-stable@freebsd.org Subject: Re: unexpected idprio 31 behavior on 9.2-BETA2 and 9.2-RC1 Message-ID: <5202063F.9070706@freebsd.org> In-Reply-To: <1375737316.96778.10.camel@firkin.mischler.com> References: <1375737316.96778.10.camel@firkin.mischler.com>
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On 2013/08/06 05:15, Dave Mischler wrote: > I have an i5-2500 machine 8GB RAM now running 9.2-RC1 amd64 with the > GENERIC kernel. Today, while still running 9.2-BETA2, I updated my > source tree and started building world with idprio 31 and I looked back > a while later and all the CPU cores and disk were essentially idle, and > hardly any progress had been made on the build. I stopped and restarted > the build without the idle priority setting and it ran fine. Anybody > else seen any of this? Anybody know about any fairly recent changes that > might account for it? > > I did a "rm -rf /usr/src /usr/obj" and loaded a new source tree before > going to RC1. I still see odd behavior at RC1. Sometimes it works just > like it should (i.e. compute bound processes use most/all of the > available CPU time), but a lot of the time both the CPU and disk are > idle (e.g. CPU 97.8% idle, disk 1% busy per systat). I don't think I > ever saw this behavior before while running "make buildworld -j4". Can > anyone else confirm/rebut my findings? Thanks. > > idle should never be used, it can cause long term priority inversion in kernel, make the system slower.
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