From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161004AbVLODd5 (ORCPT ); Wed, 14 Dec 2005 22:33:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161007AbVLODd4 (ORCPT ); Wed, 14 Dec 2005 22:33:56 -0500 Received: from mx2.suse.de ([195.135.220.15]:46543 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1161004AbVLODd4 (ORCPT ); Wed, 14 Dec 2005 22:33:56 -0500 Date: Thu, 15 Dec 2005 04:33:54 +0100 From: Andi Kleen To: Martin Peschke Cc: Andi Kleen , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [patch 1/6] statistics infrastructure - prerequisite: scatter-gather ringbuffer Message-ID: <20051215033354.GR23384@wotan.suse.de> References: <43A044AA.4040103@de.ibm.com> <43A0D68D.8090405@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43A0D68D.8090405@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Relayfs seems to be the right thing to convey streams of incremental > pieces of data, like trace records as implemented by > arch/s390/kernel/debug.c, for example. Relayfs would work for statistics > that involve data growth like a history of a counter, for example, or > the raw measurement data reported for statistic updates. I doubt it is > the right thing for counters, fill level indicators and histograms; For those we traditionally use ASCII files if the data is small. If it's big relayfs is probably the right answer. > basically for all types of statistics that do not continuously put their > hands on untouched memory to store their results. > > I am currently using debugfs, which works fine for all of these cases. > In addition, I need some ringbuffer functionality, though. IIRC relayfs was changed to be able to handle files in debuggfs by just plugging in the file operations. -Andi