Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751585AbaJFTfE (ORCPT ); Mon, 6 Oct 2014 15:35:04 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:36227 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750995AbaJFTfB (ORCPT ); Mon, 6 Oct 2014 15:35:01 -0400 X-Sasl-enc: KK8bcwQyUD2EcXXICSreJOccuwM4uH8P7PwXu/ssdK+v 1412624100 Date: Mon, 6 Oct 2014 16:34:48 -0300 From: Henrique de Moraes Holschuh To: Thomas Gleixner Cc: Christoph Lameter , Richard Cochran , linux-kernel@vger.kernel.org Subject: Re: Why do we still have 32 bit counters? Interrupt counters overflow within 50 days Message-ID: <20141006193448.GB8238@khazad-dum.debian.net> References: <20141003120345.GA6652@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-GPG-Fingerprint1: 4096R/39CB4807 C467 A717 507B BAFE D3C1 6092 0BD9 E811 39CB 4807 X-GPG-Fingerprint2: 1024D/1CDB0FE3 5422 5C61 F6B7 06FB 7E04 3738 EE25 DE3F 1CDB 0FE3 User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Tools expect the number of interrupt to increase linearly and not jump by > > 2^32 once in awhile. There are functions in the kernel (/proc/stat) that ... > I understand that, I just wonder why nobody noticed before. It's been > that way forever :) Any proper tool that interfaces to snmp-like counters expects and deals with worse: sudden counter resets. And it has been that way forever :-) So people who use such tools would hardly notice any warp-arounds... So, the question becomes: which tools are misbehaving? Maybe they should adopt snmp-like counter reset detection for peak filtering, and we could leave 32-bit alone, and increase the counter size only on for 64-bit? -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh -- 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/