Date: Sat, 13 Feb 1999 00:16:08 -0800 (PST) From: Julian Elischer <julian@whistle.com> To: "Kenneth D. Merry" <ken@plutotech.com> Cc: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>, freebsd-scsi@FreeBSD.ORG Subject: Re: Is CAM slower than the old SCSI layer for JAZ drives? Message-ID: <Pine.BSF.4.05.9902130013070.310-100000@s204m82.isp.whistle.com> In-Reply-To: <199902130347.UAA38439@panzer.plutotech.com>
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On Fri, 12 Feb 1999, Kenneth D. Merry wrote: > Andre Albsmeier wrote... > > 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) I've heard from several sources (notibly Simon Shapiro) that something in the CAM code is slowing things down. However I don't think it's likely to be a theoretical thing, but possibly an implimentation gothca.. in THEORY CAM should equal or surpass the old system, with many organisational advantages. > > julian To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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