From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <532349BF.4010307@kernel.dk> Date: Fri, 14 Mar 2014 12:26:07 -0600 From: Jens Axboe MIME-Version: 1.0 Subject: Re: Possible bug when setting compression References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: Matthew Eaton , fio@vger.kernel.org List-ID: On 03/14/2014 09:52 AM, Matthew Eaton wrote: > I have been testing iops performance using different compression > settings and found that setting either zero_buffers or > buffer_compress_percentage was not enough, I had to also set > scramble_buffers=0 in order to get the desired compression. But this > was not the case when setting refill_buffers. I tested with fio 2.1.5 > and fio from git (fio-2.1.6.1-10-g4e59d). Interesting, it would make sense to simply not scramble if the compression settings are set. That is what happens with refill_buffers right now, it has precedence over the scrambling. Or if you give a buffer pattern, that also disables the scrambling. I'll add the same for the compression settings. http://git.kernel.dk/?p=fio.git;a=commit;h=0574c885b82aea0332ab5fa35af84db0f3946726 Care to give it a test spin, just to be on the safe side? -- Jens Axboe