Date: Sun, 28 Feb 1999 21:57:44 -0600 From: David Kelly <dkelly@hiwaay.net> To: freebsd-stable@freebsd.org Subject: rc5des slows tape thruput Message-ID: <199903010357.VAA00388@nospam.hiwaay.net> In-Reply-To: Message from Matthew Jacob <mjacob@feral.com> of "Fri, 26 Feb 1999 10:06:58 PST." <Pine.LNX.4.04.9902261002120.985-100000@feral-gw>
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Mentioned the other day that I thought tape operations were slower these days than in the past. Booted my 2.2.5-RELEASE CD's and flipped over to the live filesystem to test. Used: dd if=/dev/zero bs=10k count=1000 of=/dev/rst0 In 12 runs on both DDS-1 and DDS-2 tapes got 349k/sec to 376k/sec. Didn't seem to matter which type type. Compression is jumpered off. These are the expected data rates I have seen in the past, but haven't seen recently. Booted single user into 3.0-current (as of Jan 30). Got similar results. And the same yet when multiuser doing the test as myself. But Friday night was getting half this thruput. Fired up X and repeated. Essentially the same results. Then fired up rc5des, which is niced and fell to an average of 185k/sec. Snipped from top: 294 dkelly 105 20 740K 520K RUN 9:58 97.95% 97.95% rc5des This behavior does not seem reasonable in an OS with FreeBSD's repute. System is a PPro-166/512k OC'ed to 210. Tape drive is on: ahc0: <Adaptec 2940 SCSI adapter> rev 0x00 int a irq 15 on pci0.9.0 ahc0: aic7870 Single Channel A, SCSI Id=7, 16/255 SCBs sa0 at ahc0 bus 0 target 5 lun 0 sa0: <ARCHIVE Python 28388-XXX 4.CM> Removable Sequential Access SCSI-2 device sa0: 5.0MB/s transfers (5.0MHz, offset 15) -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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