Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030531AbWBHFjU (ORCPT ); Wed, 8 Feb 2006 00:39:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030532AbWBHFjU (ORCPT ); Wed, 8 Feb 2006 00:39:20 -0500 Received: from relay02.mail-hub.dodo.com.au ([202.136.32.45]:16052 "EHLO relay02.mail-hub.dodo.com.au") by vger.kernel.org with ESMTP id S1030531AbWBHFjT (ORCPT ); Wed, 8 Feb 2006 00:39:19 -0500 From: Grant Coady To: Willy Tarreau Cc: Con Kolivas , linux-kernel@vger.kernel.org Subject: Re: 2.6 vs 2.4, ssh terminal slowdown Date: Wed, 08 Feb 2006 16:39:09 +1100 Organization: http://bugsplatter.mine.nu/ Reply-To: gcoady@gmail.com Message-ID: References: <200602081335.18256.kernel@kolivas.org> <24niu1hrom6udfa2km18b8bagad62kjamc@4ax.com> <200602081400.59931.kernel@kolivas.org> <20060208051709.GE11380@w.ods.org> In-Reply-To: <20060208051709.GE11380@w.ods.org> X-Mailer: Forte Agent 2.0/32.652 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1580 Lines: 38 Hi Willy, On Wed, 8 Feb 2006 06:17:09 +0100, Willy Tarreau wrote: >Hi Grant, > >On Wed, Feb 08, 2006 at 03:51:24PM +1100, Grant Coady wrote: >> On Wed, 8 Feb 2006 14:00:59 +1100, Con Kolivas wrote: >> >> >This is the terminal's fault. xterm et al use an algorithm to determine how >> >fast your machine is and decide whether to jump scroll or smooth scroll. This >> >algorithm is basically broken with the 2.6 scheduler and it decides to mostly >> >smooth scroll. >> >> Strange it does that over localnet to a PuTTY terminal on windoze. >> >> Seems a strange thing to do in the kernel though, presentation >> buffering / management surely can be done in userspace? > >I suspect the sshd on the firewall gets woken up for each line and it >behaves exactly like an xterm. After having done a lot of "ls -l|cat" >on 2.6, I'm not surprized at all :-/ > >A good test would be to strace sshd under 2.4 and 2.6. You could even >use strace -tt. Probably that you will see something like 1 ms between >two reads on 2.6 and nearly nothing between them in 2.4. Yes, it is nearly 1ms per line delay with 2.6, but 2.4 and 2.6 with the trailing '|cat' give similar times, didn't try that notion last time. We know now it isn't the network cards, disk I/O, just an oddness in 2.6 ;) Cheers, Grant. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/