Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030699AbWAKDNa (ORCPT ); Tue, 10 Jan 2006 22:13:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030710AbWAKDNa (ORCPT ); Tue, 10 Jan 2006 22:13:30 -0500 Received: from smtp-out.google.com ([216.239.45.12]:12059 "EHLO smtp-out.google.com") by vger.kernel.org with ESMTP id S1030699AbWAKDNa (ORCPT ); Tue, 10 Jan 2006 22:13:30 -0500 Message-ID: <43C477AD.4090308@google.com> Date: Tue, 10 Jan 2006 19:12:45 -0800 From: Martin Bligh User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051011) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Con Kolivas CC: Peter Williams , Andrew Morton , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: -mm seems significanty slower than mainline on kernbench References: <43C45BDC.1050402@google.com> <200601111249.05881.kernel@kolivas.org> <43C46F99.1000902@bigpond.net.au> <200601111407.05738.kernel@kolivas.org> In-Reply-To: <200601111407.05738.kernel@kolivas.org> Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1569 Lines: 33 Con Kolivas wrote: > On Wed, 11 Jan 2006 01:38 pm, Peter Williams wrote: > >>Con Kolivas wrote: >> > I guess we need to check whether reversing this patch helps. >> >>It would be interesting to see if it does. >> >>If it does we probably have to wear the cost (and try to reduce it) as >>without this change smp nice support is fairly ineffective due to the >>fact that it moves exactly the same tasks as would be moved without it. >> At the most it changes the frequency at which load balancing occurs. > > > I disagree. I think the current implementation changes the balancing according > to nice much more effectively than previously where by their very nature, low > priority tasks were balanced more frequently and ended up getting their own > cpu. No it does not provide firm 'nice' handling that we can achieve on UP > configurations but it is also free in throughput terms and miles better than > without it. I would like to see your more robust (and nicer code) solution > incorporated but I also want to see it cost us as little as possible. We > haven't confirmed anything just yet... Whether it turns out to be that or not ... 10% is a BIG frigging hit to take doing something basic like kernel compilation. Hell, 1% is a big hit to take, given the lengths we go to to buy that sort of benefit. M. - 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/