Date: Tue, 28 Sep 2004 09:49:26 +0200 From: Peter Holm <peter@holm.cc> To: Stephan Uphoff <ups@tree.com> Cc: "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: scheduler (sched_4bsd) questions Message-ID: <20040928074926.GA99957@peter.osted.lan> In-Reply-To: <1096339936.3733.279.camel@palm.tree.com> References: <1095468747.31297.241.camel@palm.tree.com> <414B8D5E.7000700@elischer.org> <1095529353.31297.1192.camel@palm.tree.com> <1096135220.53798.17754.camel@palm.tree.com> <41563C95.2020501@elischer.org> <20040926075218.GA85983@peter.osted.lan> <1096339936.3733.279.camel@palm.tree.com>
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On Mon, Sep 27, 2004 at 10:52:16PM -0400, Stephan Uphoff wrote: > On Sun, 2004-09-26 at 03:52, Peter Holm wrote: > > On Sat, Sep 25, 2004 at 08:50:45PM -0700, Julian Elischer wrote: > > > Stephan Uphoff wrote: > > > > > > >>Maybe something brutal like: > > > >> if ((curthread->td_ksegrp == kg) && > > > >> (td->td_priority > curthread->td_priority)) > > > >> curthread->td_flags |= TDF_NEEDRESCHED; > > > >> > > > >>in setrunqueue for > > > >>the else case of "if (kg->kg_avail_opennings > 0)" > > > >>would do the trick (without preemption) for the easy but probably more > > > >>common cases? > > > >> > > > >>Maybe I can find some time next week to think about a clean > > > >>fix. I find it always helpful having a small task in mind while reading > > > >>source code. > > > > > > > > > > > >I wrote a fix that should cover all cases. > > > >However I would like to test it a little bit before posting the patch. > > > >Is there any multi-threaded kernel torture program that you can > > > >recommend? > > > > > > > > > Peter Holm (CC'd) has a really cool set of torture tests. > > > he has also seen all sorts of failures others have not (yet) triggered. :-) > > > > > > I'm 'busy" for the next couple of weeks so you may want to communicate > > > directly with him and see if you and he together can figure out some of the > > > things he's > > > been seeing :-) > > > > > > his tests are at: > > > http://www.holm.cc/stress/src/stress.tgz > > > > > > > > > > >Thanks > > > > > > > > Stephan > > > > > > > > I'll be glad to test any patches. > > Great. > Can you try the attached patch to see if it changes any of your > previously observed behaviour? > The system still freezes and can be unfrozen by a ping: http://www.holm.cc/stress/log/stephan.html -- Peter Holm
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