Date: Fri, 19 Feb 1999 07:09:38 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: jlemon@americantv.com (Jonathan Lemon) Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Ethernet interrupt overhead Message-ID: <199902190609.HAA09674@labinfo.iet.unipi.it> In-Reply-To: <19990218221154.34584@right.PCS> from "Jonathan Lemon" at Feb 18, 99 10:11:36 pm
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> I'm seeing (as reported via systat) that the machine is spending > about 30% of it's time handling interrupts. The ethernet card is > generating just under 10,000 interrupts per second. > > This seems to translate into roughly 9,000 cycles/packet, which > seems rather high to me. Is this reasonable, or do I just have cards are different. I was doing some testing few months ago, and on a P5-90 got the following costs for receiving a full-length pkt (measured using the Pentium cycle counter on a P5-90): ed: 25.000 ticks lnc: 5.000 ticks de: 1.000 ticks the latter two cards use DMA so they make a better use of the bus bandwidth and cpu. cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO . EMAIL: luigi@iet.unipi.it . Dip. di Ing. dell'Informazione HTTP://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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