Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751000AbWIRQ3B (ORCPT ); Mon, 18 Sep 2006 12:29:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751831AbWIRQ3B (ORCPT ); Mon, 18 Sep 2006 12:29:01 -0400 Received: from minus.inr.ac.ru ([194.67.69.97]:23942 "HELO ms2.inr.ac.ru") by vger.kernel.org with SMTP id S1750977AbWIRQ3A (ORCPT ); Mon, 18 Sep 2006 12:29:00 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=ms2.inr.ac.ru; b=r7oMrGGWk4KCoJtOj/1La4e4/MNAcsQGlC6M/A2i5dAZpEiOejMel8/5NktRJXXo1tDhMf5D97/1ind5/05vGhg0chGJxwnSJ5rxAO3WSVSjW+uCQGnHZUgWUVWp9KdUslhoxp4OZk+YeFuW61btNhD55kIllxxrYE9aR2DtD9E=; Date: Mon, 18 Sep 2006 20:28:47 +0400 From: Alexey Kuznetsov To: Andi Kleen Cc: "Vladimir B. Savkin" , Jesper Dangaard Brouer , Harry Edmon , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: Network performance degradation from 2.6.11.12 to 2.6.16.20 Message-ID: <20060918162847.GA4863@ms2.inr.ac.ru> References: <4492D5D3.4000303@atmos.washington.edu> <20060918153822.GA805@ms2.inr.ac.ru> <200609181754.37623.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200609181754.37623.ak@suse.de> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1031 Lines: 30 Hello! > Hmm, not sure how that could happen. Also is it a real problem > even if it could? As I said, the problem is _occasionally_ theoretical. This would happen f.e. if packet socket handler was installed after IP handler. Then tcpdump would get packet after it is processed (acked/replied/forwarded). This would be disasterous, the results are unparsable. I recall, the issue was discussed, and that time it looked more reasonable to solve problems of this kind taking timestamp once before it is seen by all the rest of stack. Who could expect that PIT nightmare is going to return? :-) > Then it has to use the ACPI pmtmr which is really really slow. > The overhead of that thing is so large that you can clearly see it in > the network benchmark. I see. Thank you. Alexey - 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/