Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646AbbECKCT (ORCPT ); Sun, 3 May 2015 06:02:19 -0400 Received: from mout.gmx.net ([212.227.17.22]:51557 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743AbbECKCN (ORCPT ); Sun, 3 May 2015 06:02:13 -0400 Message-ID: <5545F220.1060902@gmx.de> Date: Sun, 03 May 2015 12:02:08 +0200 From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Linux Kernel Subject: periodic iowait spike Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:Gu686h8Ne5CSuW6BoNBhOdm88ETZOIvrv0fERetqeYyKbg4HDoJ 0oy5/MZNQIUTxBvJvqEHwKvEOWf/v+oxJcfrFyvlm3ipq92a9wZCRBNrgP6iWappX8tFeUP arfMMUf+g1ljlHylY9WyzSw4zDyIaATYRAeY/gOO2vD2lK/HDRjvESFGSe4Y0Y9+fCb7ezu q3c4jO0HsoL8hbSXccC2Q== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 849 Lines: 18 The picture in [1], created with isag from the sysstat package, shows a periodic spike in the iowait of my tinderbox server (hardened Gentoo 3.19.6-r1), correlating to write transactions per seconds from a similar graph. I'm wondering what (kernel, btrfs or ?) is causing this. [1] http://www.zwiebeltoralf.de/pub/sar_cpu_3rdMay.png -- Toralf pgp key: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 0076 E94E -- "; the past is all dirty and cruel in the modern popular imagination, with the exception of the Romans, who are just cruel" Ian Mortimer, 2008, "The Time Traveller's Guide to Medieval England" -- 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/