From owner-freebsd-threads@FreeBSD.ORG Thu Jul 16 17:56:58 2009 Return-Path: Delivered-To: freebsd-threads@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 62A18106566B; Thu, 16 Jul 2009 17:56:58 +0000 (UTC) (envelope-from nick@desert.net) Received: from tao.desert.net (tao.desert.net [209.104.5.188]) by mx1.freebsd.org (Postfix) with ESMTP id 37D4C8FC14; Thu, 16 Jul 2009 17:56:58 +0000 (UTC) (envelope-from nick@desert.net) Received: from motoko.vpn.desert.net (motoko.vpn.desert.net [10.24.5.6]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by tao.desert.net (Postfix) with ESMTP id 98FA65D16; Thu, 16 Jul 2009 10:56:57 -0700 (MST) Message-Id: From: Nick Esborn To: Attilio Rao In-Reply-To: <3bbf2fe10907161053x3b6aa60dneb8dbd5217b4cb03@mail.gmail.com> Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary="Apple-Mail-25-1024360403" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v935.3) Date: Thu, 16 Jul 2009 10:56:55 -0700 References: <200907152140.n6FLe42l045879@freefall.freebsd.org> <3bbf2fe10907160526l2f066698qce8a5e77aee6366b@mail.gmail.com> <3bbf2fe10907160548l74de896bka609de7a9a994899@mail.gmail.com> <6E6A9516-6C69-4E41-803C-FE5F126F402C@desert.net> <3bbf2fe10907161053x3b6aa60dneb8dbd5217b4cb03@mail.gmail.com> X-Pgp-Agent: GPGMail 1.2.0 (v56) X-Mailer: Apple Mail (2.935.3) Cc: freebsd-threads@freebsd.org Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Jul 2009 17:56:58 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-25-1024360403 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On Jul 16, 2009, at 10:53 AM, Attilio Rao wrote: > 2009/7/16 Nick Esborn : >> >> >> KDB, DDB, SCHED_ULE, and PREEMPTION are already turned on. I will >> try >> FULL_PREEMPTION, INVARIANT_SUPPORT, INVARIANTS, and WITNESS, but >> when I >> first upgraded to 8.0, this server was unable to handle its >> workload with >> the INVARIANTS and WITNESS options turned on. > > What do you mean with 'unable'? What was happening precisely? System time would rise during periods of peak demand, and the system would quickly fall behind on its workload of queries. However, I have some hardware I can dedicate to this, and only run the one MySQL data set which exhibits this problem. That should be enough of a workload reduction to allow the server to keep up even with all the above options turned on. -nick > >> Also, it can take a while for it to become clear that the deadlock >> has >> occurred -- usually our monitoring picks it up when replication falls >> behind. So it may be 15-20 minutes after the deadlock that I am >> able to run >> the above db commands. Of course the thread will still be >> deadlocked. >> Hopefully that doesn't reduce the value of the data obtained. > > It should be still fine. > > Thanks, > Attilio > > > -- > Peace can only be achieved by understanding - A. Einstein -- nick@desert.net - all messages cryptographically signed --Apple-Mail-25-1024360403 content-type: application/pgp-signature; x-mac-type=70674453; name=PGP.sig content-description: This is a digitally signed message part content-disposition: inline; filename=PGP.sig content-transfer-encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iEYEARECAAYFAkpfaegACgkQw1bX5UNr2AB6qACgvzbhe6F7Csn7uHlsREMn4V/X YT0AniKg3hfVQr+ehpZ5+LUxAihxVGpm =zL/+ -----END PGP SIGNATURE----- --Apple-Mail-25-1024360403--