Date: Wed, 07 Mar 2007 21:48:59 +0100 From: Ivan Voras <ivoras@fer.hr> To: freebsd-geom@freebsd.org Cc: freebsd-stable@freebsd.org Subject: Re: Some Unix benchmarks for those who are interesed Message-ID: <45EF253B.8030909@fer.hr> In-Reply-To: <45EF2252.1000202@fluffles.net> References: <20070306020826.GA18228@nowhere> <45ECF00D.3070101@samsco.org><20070306050312.GA2437@nowhere><008101c75fcc$210c74a0$0c00a8c0@Artem> <esk9vq$uhh$1@sea.gmane.org><001a01c7601d$5d635ee0$0c00a8c0@Artem> <eskka8$adn$1@sea.gmane.org><001801c7603a$5339e020$0c00a8c0@Artem> <eskpd1$sm4$1@sea.gmane.org> <20070307105144.1d4a382f@daydream.goid.lan><002801c760e2$5cb5eb50$0c00a8c0@Artem> <esmvnp$khs$1@sea.gmane.org><005b01c760e6$9a798bf0$0c00a8c0@Artem> <esn2s6$1i9$1@sea.gmane.org> <001601c760ee$f76fa300$0c00a8c0@Artem> <45EF2252.1000202@fluffles.net>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB56D8EB93F8A41C3F7218428 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Fluffles wrote: > If you use dd on the raw device (meaning no UFS/VFS) there is no > read-ahead. This means that the following DD-command will give lower ST= R > read than the second: >=20 > no read-ahead: > dd if=3D/dev/mirror/data of=3D/dev/null bs=3D1m count=3D1000 > read-ahead and multiple I/O queue depth: > dd if=3D/mounted/mirror/volume of=3D/dev/null bs=3D1m count=3D1000 I'd agree in theory, but bonnie++ gives WORSE results than raw device: Version 1.93c ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP xxxx.xxxx.xx 1G 305 99 59135 15 21350 7 501 99 57480 11 478.5 13 Latency 27325us 63238us 535ms 45347us 68125us 2393ms And pumping vfs.read_max to an obscene value doesn't really help: # sysctl vfs.read_max=3D256 vfs.read_max: 16 -> 256 Version 1.93c ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP xxxx.xxxx.xx 1G 305 99 57718 15 18758 6 500 99 60900 13 467.8 13 Latency 27325us 89977us 99594us 36706us 71907us 90021us I've experimented with increasing MAXPHYS (to 256K) before and it also doesn't help. --------------enigB56D8EB93F8A41C3F7218428 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF7yU7ldnAQVacBcgRAtu3AKCbXdt2Wizg7zkdpFjRBGQRImK0lgCghUGA VL+Q3UlKjcYpkfNl1Q9Hq+M= =u4zO -----END PGP SIGNATURE----- --------------enigB56D8EB93F8A41C3F7218428--
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