From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f173.google.com ([209.85.213.173]:35872 "EHLO mail-ig0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751712AbcBJTQL (ORCPT ); Wed, 10 Feb 2016 14:16:11 -0500 Received: by mail-ig0-f173.google.com with SMTP id xg9so20648252igb.1 for ; Wed, 10 Feb 2016 11:16:11 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <56BB38D4.6030008@netcologne.de> References: <56A230C3.3080100@netcologne.de> <56A6082C.3030007@netcologne.de> <56A73460.7080100@netcologne.de> <56A7CF97.6030408@gmail.com> <56A88452.6020306@netcologne.de> <56A8F18E.3070400@gmail.com> <56AF676B.2070902@netcologne.de> <56B9EE1E.2040000@netcologne.de> <56BB38D4.6030008@netcologne.de> Date: Wed, 10 Feb 2016 12:16:10 -0700 Message-ID: Subject: Re: btrfs-progs 4.4 re-balance of RAID6 is very slow / limited to one cpu core? From: Chris Murphy To: Christian Rohmann Cc: Chris Murphy , "Austin S. Hemmelgarn" , linux-btrfs Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: http://fpaste.org/320720/45511028/ What is rb_next? See if you can explode that out and find out more about why there's so much time going on with that. I see that rb_next gets used for lots of things, including btrfs. In mine, rb_next is less than 1% overhead, but for you it's the top item. That's suspicious. http://fpaste.org/320718/10016145/ line 72-73. We both have counts for qgroup stuff. Mine is much much less than yours. I have never had quotas enabled on any of my filesystems, so I don't know why there are any such counts at all. But since your values are nearly three orders of magnitude greater than mine, I have to ask if you have quotas enabled or have ever had them enabled? That might be a factor here... Chris Murphy