From: Eric Sandeen Subject: Re: [PATCH] resize2fs: radically reduce memory utilization by using rbtree bitmaps Date: Fri, 25 Jul 2014 13:11:42 -0500 Message-ID: <53D29DDE.805@redhat.com> References: <1406310671-10784-1-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: "Theodore Ts'o" , Ext4 Developers List Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56367 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752937AbaGYSLq (ORCPT ); Fri, 25 Jul 2014 14:11:46 -0400 In-Reply-To: <1406310671-10784-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 7/25/14, 12:51 PM, Theodore Ts'o wrote: > When resizing an empty 21T file system to 28T, resize2fs was using > this much CPU time and memory: > > 216.98user 19.77system 4:02.92elapsed 97%CPU (0avgtext+0avgdata 4485664maxresident)k > 8inputs+1068680outputs (0major+800745minor)pagefaults 0swaps > > After this one-line change: > > 222.29user 0.49system 3:48.79elapsed 97%CPU (0avgtext+0avgdata 30080maxresident)k > 8inputs+1068552outputs (0major+2497minor)pagefaults 0swaps > > An extra 14 seconds (+6%) of elapsed time to reduce the memory > utilization from 4.2GB to 29MB seems like a fair trade. :-) especially when it actually looks like 14 *fewer* seconds (-6%) ? -Eric