From owner-freebsd-hackers Sat Sep 23 10:29:16 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from search.sparks.net (search.sparks.net [208.5.188.60]) by hub.freebsd.org (Postfix) with ESMTP id BBABB37B424 for ; Sat, 23 Sep 2000 10:29:14 -0700 (PDT) Received: by search.sparks.net (Postfix, from userid 100) id 5982FDC74; Sat, 23 Sep 2000 13:24:07 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by search.sparks.net (Postfix) with ESMTP id 4CF76DC73 for ; Sat, 23 Sep 2000 13:24:07 -0400 (EDT) Date: Sat, 23 Sep 2000 13:24:07 -0400 (EDT) From: David Miller To: freebsd-hackers@freebsd.org Subject: Limits of TCP in FreeBSD kernel? Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hi All:) I'm looking at building an eight or twelve port fast ethernet router, and I got to wondering how well a FreeBSD box could handle that much traffic. Assume, for the moment, that hardware is not an issue. Assume that I have a gigahertz processor, 4 way interleaved memory, 4 separate fast/wide PCI busses. (Thanks to the guys on -hardware for helping me locate it) I tried ping -f localhost on an 800 MHz athlon, and netstat -w 1 -I lo0 indicated about 80,000 pps. The system was 100% busy doing this, about 85% system usage. I'm thinking this is probably spent largely switching in and out of kernel mode to a) have ping send the packet and b) respond to it. If this is correct, the number of packets it could handle while staying within kernel mode would be considerably larger. Or I could be sniffing glue and the cost of copying packets in and out would exceed that of context switching. How many packets per second could I expect to get under ideal circumstances? Thanks in advance:) --- David To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message