From owner-freebsd-stable@FreeBSD.ORG Wed May 11 06:33:03 2005 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2DBBF16A4CE for ; Wed, 11 May 2005 06:33:03 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.200]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9FAAC43D64 for ; Wed, 11 May 2005 06:33:02 +0000 (GMT) (envelope-from jsimola@gmail.com) Received: by wproxy.gmail.com with SMTP id 69so38509wri for ; Tue, 10 May 2005 23:33:02 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=t1IcYeHsTXvU7aYxtiTkza1FKat1vcg0eEWaYVyCUZ1JpDnUuXPce1GhpVA7PM3gKD1lDx2tSMpOKJddtB3qnsz7lTj0+nstNuRw5SQp7peIlXxL0+q+4vadjPjtr8vJYlkRo3FhSjZylaH+qr/S1jH8bJ4SmYeaquUgp3pO1fM= Received: by 10.54.21.18 with SMTP id 18mr103066wru; Tue, 10 May 2005 23:33:02 -0700 (PDT) Received: by 10.54.39.6 with HTTP; Tue, 10 May 2005 23:33:02 -0700 (PDT) Message-ID: <8eea04080505102333673368a9@mail.gmail.com> Date: Tue, 10 May 2005 23:33:02 -0700 From: Jon Simola To: freebsd-stable@freebsd.org In-Reply-To: <20050511054441.69092.qmail@web54008.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <42819770.9070007@gmail.com> <20050511054441.69092.qmail@web54008.mail.yahoo.com> Subject: Re: xl(4) & polling X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: jon@abccomm.com List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 May 2005 06:33:03 -0000 On 5/10/05, Rob wrote: > Interestingly: HZ=3D1000 is apparently a problem with > the xl devices (3Com 3c905B-TX), but not with the > rl devices (RealTek 8139). > What could cause that difference? Could a difference > in buffer size on the LAN card cause this? Yes. GigE cards tend to have larger packet buffers, but that certainly doesn't solve all the problems. I've been having some problems with the em cards in particular (fxp I've had no problems with) as no matter what I've tried tuning (tcprecvspace, HZ, polling knobs) I've been seeing packet loss of about 0.5%. That doesn't seem like much, but it's an awful lot to the couple thousand users behind it. Anyways, HZ=3D1000 shouldn't be a CPU problem on anything faster than a 500MHz-ish processor. There are also a few lightly documented sysctls that might be useful to play with that do things like poll during the idle loop (actual usefullness in any particular case may be void in your area, many will enter, few will win). --=20 Jon Simola Systems Administrator ABC Communications