From owner-freebsd-current@FreeBSD.ORG Thu Jul 28 08:28:46 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BED5716A41F for ; Thu, 28 Jul 2005 08:28:46 +0000 (GMT) (envelope-from pjd@darkness.comp.waw.pl) Received: from darkness.comp.waw.pl (darkness.comp.waw.pl [195.117.238.136]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0B38C43D45 for ; Thu, 28 Jul 2005 08:28:46 +0000 (GMT) (envelope-from pjd@darkness.comp.waw.pl) Received: by darkness.comp.waw.pl (Postfix, from userid 1009) id EDFEFACC59; Thu, 28 Jul 2005 10:28:44 +0200 (CEST) Date: Thu, 28 Jul 2005 10:28:44 +0200 From: Pawel Jakub Dawidek To: Julian Elischer Message-ID: <20050728082844.GW46538@darkness.comp.waw.pl> References: <42E88135.30603@elischer.org> <42E88F2B.5000108@elischer.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3sbgfNE+TCfp+/cI" Content-Disposition: inline In-Reply-To: <42E88F2B.5000108@elischer.org> User-Agent: Mutt/1.4.2i X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 5.2.1-RC2 i386 Cc: FreeBSD Current Subject: Re: Apparent strange disk behaviour in 6.0 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jul 2005 08:28:46 -0000 --3sbgfNE+TCfp+/cI Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jul 28, 2005 at 12:54:19AM -0700, Julian Elischer wrote: +> it APPEARS that teh system is swapping out running programs in order to= =20 +> store more write data! +>=20 +> experiment: +> boot to single user mode. +> type: +> mount {big partition} +> dd if=3D/dev/zero bs=3D128K of=3D/$bigpartition}/bigfile count=3D1000000 +>=20 +> notice that after a short while your dd is killed because the system is= =20 +> out of swapspace. +> (it doesn't have any) +> Why the F*ck does it need swapspace.? there are exactly 2 proceses=20 +> running in userspace +> and one of them s in wait4(). dd shows a resident size of about 170KB +> leaving about a GIGABYTE of unused RAM. +>=20 +> The system should make dd wait rather than trying to swap its pages out.. +>=20 +>=20 +> if you then do +> swapon (your swap device) +> and repeat teh command in the background, +> vmstat 1 will show you pages being faulted in and out... +> no WONDER IO goes to hell in a handbasket.. +>=20 +> Outgoing IO should never be able to force running programs out! +> It should start re-using old pages from the same file! +>=20 +> 4.11 gives a consinstent 65MB/sec with this array, for as long as I run = it.. +> 6.0 gives me 65MB for 15 seconds and then it drops to 20MB/sec and then= =20 +> 10MB/sec +> and the swap disk bursts into life. +>=20 +> the array goes from all the lights solidly on, to bursts of activity=20 +> with large gaps in between them. It looks I observed the same behaviour! I was testing GELI GEOM class and I was getting ENOMEM errors from malloc(9= ). Then, I was sure I've a memory leak, but this was only 'vmstat -m' issue so there was no memory leak and I shouldn't get ENOMEM in the first place while copying /usr/src/sys directory. I'm also able to reproduce your dd(1) test easly. Not sure when it was introduced... --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --3sbgfNE+TCfp+/cI Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFC6Jc8ForvXbEpPzQRAtDOAKCEs64AZynA6fhL0pgbYPgf43SqpACfe9sR HGMmNKG1ZvplxRYrOa5bf7A= =oELY -----END PGP SIGNATURE----- --3sbgfNE+TCfp+/cI--