Date: Wed, 15 Aug 2012 14:19:32 +0300 From: Alexander Motin <mav@FreeBSD.org> To: lev@FreeBSD.org Cc: Adrian Chadd <adrian@freebsd.org>, Doug Barton <dougb@FreeBSD.org>, current@freebsd.org Subject: Re: CURRENT as gateway on not-so-fast hardware: where is a bottlneck? Message-ID: <502B85C4.5060703@FreeBSD.org> In-Reply-To: <938388715.20120815151149@serebryakov.spb.ru> References: <157941699.20120815004542@serebryakov.spb.ru> <CAJ-Vmon86-FPs4%2BXXkQXAow1jW465pMM2Sj7ZHi_0_E9VYSFSA@mail.gmail.com> <502AE8B5.9090106@FreeBSD.org> <502B775D.7000101@FreeBSD.org> <1849591745.20120815144006@serebryakov.spb.ru> <502B82F4.1090804@FreeBSD.org> <938388715.20120815151149@serebryakov.spb.ru>
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On 15.08.2012 14:11, Lev Serebryakov wrote: > Hello, Alexander. > You wrote 15 августа 2012 г., 15:07:32: > > AM> Yes, that is what I expected to see there. If you have timecounter other > AM> then i8254, you can release i8254 from those duties to allow using it as > AM> one-shot setting hint.attimer.0.timecounter=0. Otherwise there are no > AM> options now. > > % dmesg | grep timer > pmtimer0 on isa0 > Event timer "RTC" frequency 32768 Hz quality 0 > attimer0: <AT timer> at port 0x40 on isa0 > Event timer "i8254" frequency 1193182 Hz quality 100 > % I've meant `kern.timecounter`. >>> (b) with interrupts, system works much better when it works (wire2wifi >>> speed is affected by wire2wire traffic, but to much less extent), but >>> it freezes every third minute for minute, when traffic is passed, but >>> no user-level applications including BIND and DHCP server) works at >>> all FOR MINUTE OR MORE. It not looks like 100ms lag, which could affect >>> video playback. It looks like 60-120 seconds lag! At least, in case of >>> ULE, I didn't try 4BSD yet. > AM> In this case problem may be that kernel and interrupt threads are all > AM> having absolute priorities. It means until they release the CPU, > AM> user-level may get no CPU time at all. :( > How could it be seen in KTR traces? Where could I read how to > decipher and read these traces? There is python GUI tool /usr/src/tools/sched/schedgraph.py for it. Short manual is inside. -- Alexander Motin
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