Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753172AbYH0ROW (ORCPT ); Wed, 27 Aug 2008 13:14:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751346AbYH0ROI (ORCPT ); Wed, 27 Aug 2008 13:14:08 -0400 Received: from ug-out-1314.google.com ([66.249.92.175]:49518 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751285AbYH0ROG (ORCPT ); Wed, 27 Aug 2008 13:14:06 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=Esf3bezuiDdMN8DmvhsOM1MvQtkj2D0dgTxBh/oFso0Xu/M9y8MkkfiS4rcC/ezcYP 0waVZMTFpepBX0rkKf4OJXfz/usQX0OswhwoVNjIfcNbIR7Un8K6pe1WtJbGclcBaW+0 f12vW3VfGQrhOuehOVehWEj62SP4VlXNRhkn0= Message-ID: <48B58B77.2000101@gmail.com> Date: Wed, 27 Aug 2008 19:14:31 +0200 From: Jarek Poplawski User-Agent: Mozilla-Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Stephen Hemminger CC: Andi Kleen , Evgeniy Polyakov , Eric Dumazet , Denys Fedoryshchenko , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: loaded router, excessive getnstimeofday in oprofile References: <200808220457.40892.denys@visp.net.lb> <20080826201406.GA24827@2ka.mipt.ru> <48B46B48.7030609@cosmosbay.com> <20080826205158.GA15266@2ka.mipt.ru> <87vdxmr53f.fsf@basil.nowhere.org> <20080827091706.574f2fae@extreme> In-Reply-To: <20080827091706.574f2fae@extreme> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1820 Lines: 45 Stephen Hemminger wrote, On 08/27/2008 06:17 PM: > On Wed, 27 Aug 2008 14:54:12 +0200 > Andi Kleen wrote: > >> Evgeniy Polyakov writes: >>> Yup, this innocent toys can end up with this such behaviour on modern >>> highly loaded machines. >> I and also other people had some patches to move the time stamp >> measuring into the socket. This way the time stamping didn't need to >> be enabled on all packets, only on those that actually end up at a >> socket that requires the time stamp. >> >> Unfortunately DaveM didn't like it because some bank wanted >> different semantics, see the discussion in >> http://thread.gmane.org/gmane.linux.network/91679 >> >> Perhaps you can find out which bank it was and send them a bill for >> your CPU time ;-) >> >> -Andi >> > > Look at /proc/net/ptype to see if any AF_PACKET sockets are open. > There are several causes of this: > * Applications like DHCP use AF_PACKET when they could use something else > * AF_PACKET API was poorly designed and always has timestamps > * The choice was made to get more accurate timestamps by stamping early in > receive code. A better alternative would be to do it in protocol handler > after the socket filter. Sorry, Andi socket layer is too late. > * No driver is using hardware mechanisms to get accurate/free timestamps. > I was working on sky2, but never was stable/complete. > > Easist advice now is to fix userspace. And what is working advice? Why exactly admin can't chose between 2 alternatives here? Jarek P. -- 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/