From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com [32.97.182.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e1.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 711CD679EB for ; Sat, 1 Apr 2006 04:03:24 +1100 (EST) Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e1.ny.us.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id k2VH3LQs008299 for ; Fri, 31 Mar 2006 12:03:21 -0500 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.12.10/NCO/VER6.8) with ESMTP id k2VH3LLt202394 for ; Fri, 31 Mar 2006 12:03:21 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11/8.13.3) with ESMTP id k2VH3LIH002243 for ; Fri, 31 Mar 2006 12:03:21 -0500 Date: Fri, 31 Mar 2006 11:03:19 -0600 To: "Jeffrey V. Merkey" Subject: Re: [PATCH]: e1000: prevent statistics from getting garbled during reset. Message-ID: <20060331170319.GV2172@austin.ibm.com> References: <20060330213928.GQ2172@austin.ibm.com> <20060331000208.GS2172@austin.ibm.com> <442C8069.507@wolfmountaingroup.com> <20060331003506.GU2172@austin.ibm.com> <442CACC0.1060308@wolfmountaingroup.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <442CACC0.1060308@wolfmountaingroup.com> From: linas@austin.ibm.com (Linas Vepstas) Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jesse.brandeburg@intel.com, linuxppc-dev@ozlabs.org, john.ronciak@intel.com, jeffrey.t.kirsher@intel.com, linux-pci@atrey.karlin.mff.cuni.cz, Jeff Garzik List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Mar 30, 2006 at 09:14:56PM -0700, Jeffrey V. Merkey wrote: > Yes, we need one. The adapter needs to maintain these stats from the > registers in the kernel structure and not > its own local variables. Did you read the code to see what the adapter does with these stats? Among other things, it uses them to adaptively modulate transmit rates to avoid collisions. Just clearing the hardware-private stats will mess up that function. > That way, when someone calls to clear the stats > for testing and analysis purposes, > they zero out and are reset. 1) ifdown/ifup is guarenteed to to clear things. Try that. 2) What's wrong with taking deltas? Typical through-put performance measurement is done by pre-loading the pipes (i.e. running for a few minutes wihtout measuring, then starting the measurement). I'd think that snapshotting the numbers would be easier, and is trivially doable in user-space. I guess I don't understand why you need a new kernel featre to imlement this. --linas From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751035AbWCaRDe (ORCPT ); Fri, 31 Mar 2006 12:03:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751334AbWCaRDe (ORCPT ); Fri, 31 Mar 2006 12:03:34 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:18409 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751033AbWCaRDd (ORCPT ); Fri, 31 Mar 2006 12:03:33 -0500 Date: Fri, 31 Mar 2006 11:03:19 -0600 To: "Jeffrey V. Merkey" Cc: john.ronciak@intel.com, jesse.brandeburg@intel.com, jeffrey.t.kirsher@intel.com, Jeff Garzik , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, linuxppc-dev@ozlabs.org Subject: Re: [PATCH]: e1000: prevent statistics from getting garbled during reset. Message-ID: <20060331170319.GV2172@austin.ibm.com> References: <20060330213928.GQ2172@austin.ibm.com> <20060331000208.GS2172@austin.ibm.com> <442C8069.507@wolfmountaingroup.com> <20060331003506.GU2172@austin.ibm.com> <442CACC0.1060308@wolfmountaingroup.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <442CACC0.1060308@wolfmountaingroup.com> User-Agent: Mutt/1.5.9i From: linas@austin.ibm.com (Linas Vepstas) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 30, 2006 at 09:14:56PM -0700, Jeffrey V. Merkey wrote: > Yes, we need one. The adapter needs to maintain these stats from the > registers in the kernel structure and not > its own local variables. Did you read the code to see what the adapter does with these stats? Among other things, it uses them to adaptively modulate transmit rates to avoid collisions. Just clearing the hardware-private stats will mess up that function. > That way, when someone calls to clear the stats > for testing and analysis purposes, > they zero out and are reset. 1) ifdown/ifup is guarenteed to to clear things. Try that. 2) What's wrong with taking deltas? Typical through-put performance measurement is done by pre-loading the pipes (i.e. running for a few minutes wihtout measuring, then starting the measurement). I'd think that snapshotting the numbers would be easier, and is trivially doable in user-space. I guess I don't understand why you need a new kernel featre to imlement this. --linas