From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [branch:bcachefs-testing][tier] Massive slow down after some time Date: Sun, 6 Nov 2016 05:32:19 -0900 Message-ID: <20161106143219.jvstkt7ucjyxhr5p@kmo-pixel> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pf0-f175.google.com ([209.85.192.175]:35286 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751830AbcKFOcX (ORCPT ); Sun, 6 Nov 2016 09:32:23 -0500 Received: by mail-pf0-f175.google.com with SMTP id i88so77234401pfk.2 for ; Sun, 06 Nov 2016 06:32:23 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Marcin Cc: linux-bcache@vger.kernel.org On Sun, Nov 06, 2016 at 03:04:12PM +0100, Marcin wrote: > Hi! > I'm trying mentioned branch. I've got tiered bcachefs witch lz4 compresion > turned on. > After some times of copying of files into bcachefs I noticed huge slow downa > of writing. Htop shows that kernel thread bcache_gc consumes a lot of CPU > and spends a lot of time waiting for I/O. Iostat shows that almost all > I/Ooperations goes to tier 1. In dmesg I see a couple of repeated messages > (they appears together, "INFO: task kworker/u8:2:11787 blocked for more than > 120 seconds." with "INFO: task rsync:11935 blocked for more than 120 > seconds." : Sounds like tiering isn't freeing up space on tier 0... Can you check cache0/alloc_debug (assuming cache0 is your tier 0 device) to confirm? After that, could you hammer on single device mode for awhile? I need to know if I'm just looking for tiering bugs, or if the btree changes have issues.