Date: Fri, 12 Feb 1999 19:17:23 +0100 From: Andre Albsmeier <andre.albsmeier@mchp.siemens.de> To: freebsd-scsi@FreeBSD.ORG Subject: Is CAM slower than the old SCSI layer for JAZ drives? Message-ID: <19990212191723.A644@internal>
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I have made an odd observation. Copying a large file from my 100MBit net to a 2GB jaz, I noticed that 3.1-BETA took a lot more time than it used to under 2.2.8-STABLE. Exact (well, as exact as dd can be) measurements told me: 3.1-BETA: 135447409 bytes transferred in 178.638903 secs (758219 bytes/sec) 2.2.8-STABLE: 135447409 bytes transferred in 87.649259 secs (1545334 bytes/sec) This is nearly exact twice the time for 3.1 than for 2.2.8. The network is okay, a dd to /dev/null gives me: 135447409 bytes transferred in 13.553990 secs (9993176 bytes/sec) Copying the same file to a "normal harddrive" results in: 135447409 bytes transferred in 19.716693 secs (6869682 bytes/sec) This I would assume as OK. Is there something special in the CAM layer that has to do with IOMEGA drives (apart from the quirk entry for tagged queuing in cam_xpt.c)? Should I do some debugging? Thanks, -Andre To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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