From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: loaded router, excessive getnstimeofday in oprofile Date: Thu, 28 Aug 2008 12:36:45 -0700 (PDT) Message-ID: <20080828.123645.78561286.davem@davemloft.net> References: <21915755.1327801219904892242.JavaMail.root@ouachita> <20080828072218.GI26610@one.firstfloor.org> <200808281948.52608.denys@visp.net.lb> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: andi@firstfloor.org, jmalicki@metacarta.com, johnpol@2ka.mipt.ru, dada1@cosmosbay.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, juhlenko@akamai.com, sammy@sammy.net To: denys@visp.net.lb Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:42550 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754032AbYH1Tgu (ORCPT ); Thu, 28 Aug 2008 15:36:50 -0400 In-Reply-To: <200808281948.52608.denys@visp.net.lb> Sender: netdev-owner@vger.kernel.org List-ID: From: Denys Fedoryshchenko Date: Thu, 28 Aug 2008 19:48:52 +0300 > So there is few good solutions available (IMHO): > 1)Introduce some SO_REALTIMESTAMP (anyway even SO_TIMESTAMP not defined in any > standard) for banks and ntp folks, who need them. And even give them timespec > instead timeval, so they will be even more happy with resolution. > 2)Provide sysctl,kernel boot, or even "build time" option for "banks" to have > high resolution(and expensive) SO_TIMESTAMP. The performance hit hurts, but changing the default to lower resolution after it having been high resolution for 10+ years is a regression and something we really can't do.