From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757575AbbCCWEg (ORCPT ); Tue, 3 Mar 2015 17:04:36 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36268 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756136AbbCCWEe (ORCPT ); Tue, 3 Mar 2015 17:04:34 -0500 Date: Tue, 3 Mar 2015 14:04:33 -0800 From: Andrew Morton To: Fabian Frederick Cc: linux-kernel@vger.kernel.org, Jonathan Corbet , Ingo Molnar , Peter Zijlstra , linux-doc@vger.kernel.org Subject: Re: [PATCH 1/1 linux-next RESEND] task IO accounting: add conditional read/write counters Message-Id: <20150303140433.87a0b7232b6ebc39a00d6704@linux-foundation.org> In-Reply-To: <1425413796-2203-1-git-send-email-fabf@skynet.be> References: <1425413796-2203-1-git-send-email-fabf@skynet.be> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 3 Mar 2015 21:16:35 +0100 Fabian Frederick wrote: > This patch adds syscre and syscwe respectively effective read/write > syscall counters. We already had syscr/syscw which were > unconditionally incremented. Doing the difference between those > variables could give interesting statistics. I don't think that "could give interesting statistics" is sufficient justification for adding overhead and extending the Linux userspace interface. More specificity would help, including real-worldish use cases which demonstrate the value.