Date: Sat, 20 Feb 1999 12:30:43 -0700 (MST) From: "Kenneth D. Merry" <ken@plutotech.com> To: ru@ucb.crimea.ua (Ruslan Ermilov) Cc: gibbs@FreeBSD.ORG, stable@FreeBSD.ORG Subject: Re: Tagged queueing Message-ID: <199902201930.MAA13801@panzer.plutotech.com> In-Reply-To: <19990219233927.A4953@ucb.crimea.ua> from Ruslan Ermilov at "Feb 19, 1999 11:39:27 pm"
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Ruslan Ermilov wrote... > Hi! > > When my system was running 2.2.8-STABLE, > I had AHC_TAGENABLE in the kernel, and it > worked fine, at least dmesg reported that. > > Now, on a 3.1-STABLE (today's freshness) > it doesn't. > > `dmesg' output and kernel config are attached. > > Any clue on what has happened? The AHC_TAGENABLE option is no longer necessary. Tagged queueing is enabled by default. The reason your drive does not have tagged queueing enabled is because it is a Western Digital Enterprise drive: da0 at ahc0 bus 0 target 0 lun 0 da0: <WDIGTL ENTERPRISE 1.80> Fixed Direct Access SCSI-2 device da0: 40.000MB/s transfers (20.000MHz, offset 8, 16bit) da0: 4157MB (8515173 512 byte sectors: 64H 32S/T 4157C) Andrew Gallatin reported that his western digital enterprise drives only get 1.5MB/sec throughput with tagged queueing turned on, and 8MB/sec throughput with tagged queueing turned off. Therefore, we have a quirk entry in the transport layer that disables tagged queueing for those drives. Next time, if you have the cash, get an IBM or Seagate disk. They generally write much better disk firmware. Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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