Date: Sat, 25 Aug 2007 21:33:33 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Robert Watson <rwatson@FreeBSD.org> Cc: freebsd-current@FreeBSD.org Subject: Re: idprio(1) broken in recent -current Message-ID: <20070825113333.GA18197@turion.vk2pj.dyndns.org> In-Reply-To: <20070823192322.GQ1161@turion.vk2pj.dyndns.org> References: <20070823101737.GA1161@turion.vk2pj.dyndns.org> <20070823162802.T2662@fledge.watson.org> <20070823192322.GQ1161@turion.vk2pj.dyndns.org>
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--HcAYCG3uE/tztfnV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2007-Aug-24 05:23:22 +1000, Peter Jeremy <peter@turion.vk2pj.dyndns.org>= wrote: >boinc_client is supposed to write a watchdog flag in a shared SysV SHM >block every second. The setiathome process regularly polls the SHM >and if it doesn't see the watchdog for 31 seconds, it will abort. >boinc_client basically sits in a loop and uses select() timeouts. >I wrote a program to monitor the SHM and it shows that SHM is not >being updated. > >It looks like the kernel isn't cleanly handling the situation where >there are multiple idprio processes. I will try some more experimenting >this evening. Sorry for the delay. The select() in boinc_client is not timing out and so isn't returning until the child process dies. When I 'nice' boinc_client, 'ps' shows is waiting in 'select' - which is what I would expect. When I 'idprio' it, 'ps' shows it remaining running, though it is non-responsive. The setiathome process is deliberately allowing context switches (by calling usleep() regularly). It looks like a recent scheduler change means that multiple idprio processes don't round-robin but instead re-schedules the previously running process. I'm running SCHED_4BSD. Pity I don't have dtrace... --=20 Peter Jeremy --HcAYCG3uE/tztfnV Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFG0BON/opHv/APuIcRAjQ8AJ9EcdKuleW7o8nXe1FD8rRRiuFYgQCfRcEf fwRQ6TfuYSdCvxR3v7pAkj0= =0GmH -----END PGP SIGNATURE----- --HcAYCG3uE/tztfnV--
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