From: Lukas Czerner Subject: Re: [RFC][PATCH 0/3] add FALLOC_FL_NO_HIDE_STALE flag in fallocate Date: Wed, 18 Apr 2012 13:39:06 +0200 (CEST) Message-ID: References: <1334681618-9452-1-git-send-email-wenqing.lz@taobao.com> <4F8DAAFE.40500@redhat.com> <20120418113810.GA3447@gmail.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Andreas Dilger , Eric Sandeen , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , Zheng Liu To: Zheng Liu Return-path: In-Reply-To: <20120418113810.GA3447@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, 18 Apr 2012, Zheng Liu wrote: > > I auspect the real problem may be the lazy inode table zeroing being done in the kernel. If the test is run immediately after formatting the filesystem, then the kernel thread is busy writing to the disk in the background and interfering with your benchmark. > > > > Please format the filesystem with "-E lazy-itable-init=0", to avoid this behavior. > > I format the filesystem with this option, but it seems that it is > useless. What do you mean by that ? It does not work as it's supposed to ? ext4lazyinit kernel thread is still running ? Or the slowdown was not caused by the lazy init in the first place ? Thanks! -Lukas