Date: Thu, 20 Jan 2005 19:48:38 +0100 From: Emanuel Strobl <emanuel.strobl@gmx.net> To: freebsd-stable@freebsd.org Subject: Higher ATA-Mode -> lower speed Message-ID: <200501201948.42707.emanuel.strobl@gmx.net>
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--nextPart2359445.XJB2V7ZaMH Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Dear ata interested guys, I observed a strange behaviour which seems to explain my often noticed "16M= B/s=20 hard-limit" I have a UDMA133 drive (MAXTOR 6L060J3) which saturates at 16MB/s when I du= mp=20 anything to it, regardless of the block size. This transfer rate is reached= =20 with bs=3D4k and doesn't increase any more even not with bs=3D64k. Now, when I set the mode to UDMA100 I get well over 40MB/s!!!! Can anybody confirm that for different hw? Especially people like fandino w= ho=20 already discussed poor ata performance on -current (~16 Oct. 04). Why does UDMA133 mode limit the transfer speed so badly? And why do I get=20 significantly slower transfer rates (32MB/s insted of 42MB/s) when I set th= e=20 mode to UDMA66 (compared to UDMA100 but twice the speed of UDMA133)? There'= s=20 only one device on the channel, so UDMA66 should be fine for 42MB/s. The controller is a HPT372. Best regards, =2DHarry --nextPart2359445.XJB2V7ZaMH Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQBB7/0KBylq0S4AzzwRAlXlAKCLCXNUVkjXQmNWDV4Hd/kOg4dNGQCfW9LK uuUs0LRqrsuhqlS4qEseVU8= =T5QT -----END PGP SIGNATURE----- --nextPart2359445.XJB2V7ZaMH--
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