From owner-freebsd-net@FreeBSD.ORG Mon Jun 21 12:19:53 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 973AA16A4D0 for ; Mon, 21 Jun 2004 12:19:53 +0000 (GMT) Received: from wren.cs.unc.edu (wren.cs.unc.edu [152.2.128.86]) by mx1.FreeBSD.org (Postfix) with ESMTP id 42C7943D2F for ; Mon, 21 Jun 2004 12:19:53 +0000 (GMT) (envelope-from le@cs.unc.edu) Received: from quartet.cs.unc.edu (quartet.cs.unc.edu [152.2.133.252]) by wren.cs.unc.edu (8.12.10/8.12.10) with ESMTP id i5LCJjbk014633; Mon, 21 Jun 2004 08:19:46 -0400 (EDT) Received: from quartet.cs.unc.edu (localhost.localdomain [127.0.0.1]) by quartet.cs.unc.edu (8.12.11/8.12.11) with ESMTP id i5LCJj7A018626; Mon, 21 Jun 2004 08:19:45 -0400 Received: (from le@localhost) by quartet.cs.unc.edu (8.12.11/8.12.11/Submit) id i5LCJjnd018624; Mon, 21 Jun 2004 08:19:45 -0400 Date: Mon, 21 Jun 2004 08:19:45 -0400 From: Long Le To: freebsd-net@freebsd.org Message-ID: <20040621121945.GB18534@quartet.cs.unc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Subject: Blasting UDP packets on a 1-Gbps link X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jun 2004 12:19:53 -0000 Hi all, I've been trying to get iperf to blast UDP packets for 10 minutes on a 1-Gbps link. However, iperf stops after a few seconds and complains that it can't write to the socket because no buffer space is available. 'netstat -m' shows that there are lots of mbufs available. I modified iperf source code to set the socket's send buffer to 200000 bytes (*) but it didn't really help much. In another attempt, I modified iperf source code such that it would not quit after failing to write to the socket. However, this caused iperf to hang. I use iperf 1.7.0 and FreeBSD 4.5. The machine I am using has a 1-GHz CPU and 1 Gbytes of memory. I could try to write my own program to blast UDP packets but would prefer to use available software if possible. Has anyone successfully blasted UDP packets on a 1-Gbps link for a sustained period and can anyone give me some useful hints? Thanks, Long (*) Apparently, iperf doesn't have an option to set the socket buffer for UDP sockets. And there seems to be a limit that doesn't allow to set a larger buffer size than around 200000 bytes (this is not related to iperf but FreeBSD in general).