From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Fairbairn Subject: Re: Poor network performance with cable modem assigned to guest Date: Sat, 29 Aug 2009 10:24:18 +0100 Message-ID: References: <200908281335.13684.iggy@theiggy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE To: kvm@vger.kernel.org Return-path: Received: from lo.gmane.org ([80.91.229.12]:52250 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751972AbZH2JYk (ORCPT ); Sat, 29 Aug 2009 05:24:40 -0400 Received: from list by lo.gmane.org with local (Exim 4.50) id 1MhKAq-0002AG-U1 for kvm@vger.kernel.org; Sat, 29 Aug 2009 11:24:40 +0200 Received: from cpc1-cmbg9-0-0-cust9.cmbg.cable.ntl.com ([82.16.96.10]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 29 Aug 2009 11:24:40 +0200 Received: from jon.fairbairn by cpc1-cmbg9-0-0-cust9.cmbg.cable.ntl.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 29 Aug 2009 11:24:40 +0200 Sender: kvm-owner@vger.kernel.org List-ID: Brian Jackson writes: > On Friday 28 August 2009 01:14:42 pm Jon Fairbairn wrote: >> I'm experimenting with a virtual router. I did this a few years ago = with >> Xen and it worked well enough, but then fedora changed and it stoppe= d >> working, so I gave up for a while. Now I have a machine that support= s >> hardware virtualisation, I thought I'd try again. >> >> The setup was done through virt-manager. The network between the hos= t >> and guest is a virtual bridge. What I've been trying to do is to ass= ign >> a USB cable modem to the guest, > > > This is probably your problem here. KVM only emulates a usb1.1 > controller, that shouldn't be a problem as the cable modem is only a usb 1.1 device= =2E > and from all reports, it doesn't really do that very well. Not very well? We're talking about a factor of *FIFTY* slow down here. If I'd implemented the driver in a 1980s lazy functional language I would have only expected a factor of ten :-P ;-). > There have been numerous reports of poor performance even for a usb1.= 1 > device. You should check the archives to see if there was ever any > kind of tips or resolution to some of those problems. I had a look, but I couldn't find anything helpful. Maybe I'm searching for the wrong things? --=20 J=C3=B3n Fairbairn Jon.Fairbairn@cl.cam= =2Eac.uk