Date: Thu, 3 Feb 2000 10:50:32 -0800 (PST) From: Matthew Jacob <mjacob@feral.com> To: "Kenneth D. Merry" <ken@kdm.org> Cc: Thomas Stromberg <tstromberg@rtci.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Suggestions for Gigabit cards for -CURRENT Message-ID: <Pine.BSF.4.05.10002031034170.64395-100000@semuta.feral.com> In-Reply-To: <20000202113259.A43505@panzer.kdm.org>
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> The FreeBSD driver (written by Matt Jacob) is based on the Linux driver, > which Intel wrote, and he hasn't yet managed to get decent throughput > through the cards. (Maybe Matt will comment.) They also only have 64K of > memory on board, which is insufficient for a heavily loaded server, IMO. That's not memory- that's FIFO- there are two of them, I believe, one for receive, the other for xmit. You can devote 64k to ring descriptors for receive- that's 4096 descriptors- each able to manage a 2k buffer. And you can have two receive rings. You can have the same size for xmit. So, the receive performance bottleneck for this chip/board will be in how good your PCI implementation is at first followed by how low an amount of interrupt latency for reinstruct. If your PCI implementation can keep up with Gigabit speeds, you're fine. If not, I'm not sure that 512K or 1MB buffering buys you much. -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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