From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cloud1-vm154.de-nserver.de ([178.250.10.56]:39705 "EHLO cloud1-vm154.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbdBRHVn (ORCPT ); Sat, 18 Feb 2017 02:21:43 -0500 To: "linux-btrfs@vger.kernel.org" From: Stefan Priebe - Profihost AG Subject: high cpu usage due to btrfs_find_space_for_alloc and rb_next Message-ID: <02d3d58e-a254-eda5-a18a-36983d1e9f78@profihost.ag> Date: Sat, 18 Feb 2017 08:16:16 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi, is there any chance to optimize btrfs_find_space_for_alloc / rb_next on big devices? I've plenty of free space but most of the time there's only low I/O but high cpu usage. perf top shows: 60,41% [kernel] [k] rb_next 9,74% [kernel] [k] btrfs_find_space_for_alloc 5,55% [kernel] [k] tree_search_offset.isra.25 # btrfs filesystem df /backup/ Data, single: total=14.85TiB, used=14.37TiB System, single: total=32.00MiB, used=2.27MiB Metadata, single: total=63.00GiB, used=54.87GiB GlobalReserve, single: total=512.00MiB, used=80.17MiB -- Stefan