Date: Mon, 25 Jul 2005 12:46:58 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Daniel O'Connor <doconnor@gsoft.com.au> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/geom/zero g_zero.c src/sys/modules/geom/geom_zero Makefile Message-ID: <20050725104658.GP46538@darkness.comp.waw.pl> In-Reply-To: <200507251944.58345.doconnor@gsoft.com.au> References: <200507251003.j6PA3Gr7003418@repoman.freebsd.org> <200507251944.58345.doconnor@gsoft.com.au>
next in thread | previous in thread | raw e-mail | index | archive | help
--cotvrx6Jh20JAKQm Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 25, 2005 at 07:44:57PM +0930, Daniel O'Connor wrote: +> On Monday 25 July 2005 19:33, Pawel Jakub Dawidek wrote: +> > Add a very simple and small GEOM class - ZERO. +> > It creates very huge provider (41PB) /dev/gzero. +> > On BIO_READ request it zero-fills bio_data and on BIO_WRITE it does +> > nothing. You can also set kern.geom.zero.clear sysctl to 0 to do nothi= ng +> > even for BIO_READ. +> > +> > I'm using it for performance testing where it is very helpful. +>=20 +> How long does a newfs take on that? You will not be able to newfs this actually, but you can do other interesting tests like: - GEOM throughput: # dd if=3D/dev/gzero of=3D/dev/null bs=3D1m count=3D10000 - Overhead when adding more levels: # gnop gzero # gnop gzero.nop # gnop gzero.nop.nop # gnop gzero.nop.nop.nop # gnop gzero.nop.nop.nop.nop # dd if=3D/dev/gzero of=3D/dev/null bs=3D1m count=3D10000 # dd if=3D/dev/gzero.nop.nop.nop.nop.nop of=3D/dev/null bs=3D1m count=3D10= 000 - Test performance of various classes. And much more:) --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --cotvrx6Jh20JAKQm Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFC5MMiForvXbEpPzQRAusAAKDKFB5sbLDNgTnX2Ng9gcfteVW52gCguHBs uVodV+RVJd8PuZ3n7ML9ZCY= =c5jV -----END PGP SIGNATURE----- --cotvrx6Jh20JAKQm--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050725104658.GP46538>