Date: Fri, 03 Dec 1999 10:12:07 -0700 From: "Justin T. Gibbs" <gibbs@FreeBSD.org> To: mjacob@feral.com Cc: "Justin T. Gibbs" <gibbs@plutotech.com>, scsi@FreeBSD.ORG Subject: Re: Tape driver problems Message-ID: <199912031712.KAA00529@caspian.plutotech.com> In-Reply-To: Your message of "Fri, 03 Dec 1999 09:55:51 PST." <Pine.BSF.4.05.9912030954410.12054-100000@semuta.feral.com>
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>> The bounce buffering code doesn't perform coalessing of data yet because >> I never found an algorithm I liked for it. The NetBSD approach of >> making the bounce buffer 64K big and copying the whole thing if any >> portion needs to be bounced doesn't appeal to me (it doesn't scale >> well and consumes much too much memory). > >You pay for what you get. If you are really still using ISADMA mass >storage, blow 128k or MAXPHYS already.. IMO... We do, but we allocate and dole it out as individual pages. NetBSD allocates MAXPHYS per possible transaction on each card which turns out to be 1MB of < 16MB memory per card. This doesn't scale. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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