Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161183AbWAHKyJ (ORCPT ); Sun, 8 Jan 2006 05:54:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161182AbWAHKyJ (ORCPT ); Sun, 8 Jan 2006 05:54:09 -0500 Received: from willy.net1.nerim.net ([62.212.114.60]:40460 "EHLO willy.net1.nerim.net") by vger.kernel.org with ESMTP id S1161183AbWAHKyI (ORCPT ); Sun, 8 Jan 2006 05:54:08 -0500 Date: Sun, 8 Jan 2006 11:54:01 +0100 From: Willy Tarreau To: Bernd Eckenfels Cc: linux-kernel@vger.kernel.org, gcoady@gmail.com Subject: Re: Why is 2.4.32 four times faster than 2.6.14.6?? Message-ID: <20060108105401.GI7142@w.ods.org> References: <20060108095741.GH7142@w.ods.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1752 Lines: 67 On Sun, Jan 08, 2006 at 11:23:37AM +0100, Bernd Eckenfels wrote: > Willy Tarreau wrote: > > It's rather strange that 2.6 *eats* CPU apparently doing nothing ! > > it eats it in high interrupt load. *high* ? he never goes far beyond 1000/s ! > And it is caused by the pty-ssh-tcp output, quite possibly, but I'd rather think it's more precisely related to the ping-pong in the scheduler between grep, cut and ssh. I had the same symptom with 'ls' in xterm with lots of files. It took tens of seconds to list 2000 files while 'ls |cat' gave the same result instantly. I also have another example (2.6.15-rc5, dual athlon, logged in via SSH) : willy@pcw:willy$ time ls -l real 0m0.150s user 0m0.016s sys 0m0.024s Now if I start 4 processes in background : willy@pcw:willy$ time ls -l real 0m4.432s user 0m0.028s sys 0m0.008s With 8 processes in background : willy@pcw:willy$ time ls -l real 0m49.817s user 0m0.020s sys 0m0.008s willy@pcw:willy$ time ls -l | wc -l 1259 real 0m18.917s user 0m0.016s sys 0m0.012s I think my case with 4 processes on a dual CPU ressembles Grant's case with 2 processes on single CPU. The background processes are only ones which eat CPU half of their time, which might sometimes match an I/O bound process such as grep from a disk. > so most likely those are eepro100 interrupts. I don't think so. > Gruss > Bernd Regards, Willy PS: please don't remove people in CC: - 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/