On Wed, 23 Apr 2003, John Baldwin wrote: > On 23-Apr-2003 Craig Reyenga wrote: > > From: "John Baldwin" <jhb_at_freebsd.org> > >> > >> On 23-Apr-2003 Craig Reyenga wrote: > >> > While running a samba benchmark, I tried 'renice -n -20 10' (pid 10 is > > idle > >> > thread) to see what would happen. Turns out that this operation isn't > >> > illegal, and the system hung accordingly. The benchmark timed out soon > >> > after, and the console started displaying this message: > >> > > >> > swap_pager: indefinite wait buffer: device: ad0s1b, blkno: 776, size: > > 4096 > >> > > >> > over and over, although not rapidly. I'm not sure what to blame; perhaps > >> > setpriority() should return [EINVAL] or something. I can provide more > > info, > >> > upon request. > >> > >> Umm, yeah, setpriority should do an EINVAL, but that's not probably the > >> real bug. idlethreads are never on the run queues, they are truly idle > >> and only executed when there is nothing else to do. They don't have a > >> real priority other than "anything else is more important". What might > > have > >> happened is that setpiority() put the idle process on the run queue, which > >> is guaranteed to totally hose your system. > >> > >> Are you using SCHED_ULE or SCHED_4BSD? > > > > I am using SHED_ULE, and I have not yet tried this with SCHED_4BSD. I have > > already submitted a PR about this, perhaps a little prematurely. It's > > definitely a 'problem' though, because the system becomes unusable. I should > > also mention that any SSH sessions that were open already still work, until > > I try to run a new process, such as ls or something. > > Ok, it could be that sched_ule is breaking because of the kseq_nice > stuff. I think that SCHED_4BSD should be ok with this. On the topic of nice for the idle process(es), shouldn't they be running with the highest allowable value (+20)? Though this has no technical impact, couldn't they get that nice value for aesthetic purposes? Regards, > Andre Guibert de Bruet | Enterprise Software Consultant > > Silicon Landmark, LLC. | http://siliconlandmark.com/ >Received on Wed Apr 23 2003 - 10:39:35 UTC
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