From owner-freebsd-hackers Fri Feb 19 0:21:23 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (Postfix) with SMTP id DE87B11540 for ; Fri, 19 Feb 1999 00:21:15 -0800 (PST) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id HAA09674; Fri, 19 Feb 1999 07:09:38 +0100 From: Luigi Rizzo Message-Id: <199902190609.HAA09674@labinfo.iet.unipi.it> Subject: Re: Ethernet interrupt overhead To: jlemon@americantv.com (Jonathan Lemon) Date: Fri, 19 Feb 1999 07:09:38 +0100 (MET) Cc: freebsd-hackers@FreeBSD.ORG In-Reply-To: <19990218221154.34584@right.PCS> from "Jonathan Lemon" at Feb 18, 99 10:11:36 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1061 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > 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