From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: Bug with --buffer_compress_percentage References: <56533A11.4050706@kernel.dk> <56533BE5.3010606@kernel.dk> From: Jens Axboe Message-ID: <5653D5EA.1060201@kernel.dk> Date: Mon, 23 Nov 2015 20:13:46 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: Matthew Eaton Cc: fio@vger.kernel.org List-ID: On 11/23/2015 03:15 PM, Matthew Eaton wrote: >>> I think this is an artifact of how gzip compression works, it doesn't >>> have an unlimited size window. It's 32k, iirc. Fio should fill so that >>> it ideally would compress to the given size with an ideal compression >>> algorithm. >>> >>> You'd probably want to use buffer_compress_chunk=x to always force fio >>> to operate in sizes of that for compression, if you want to ensure that >>> gzip would be able to compress to the specified ratio. I do think we >>> have a loop missing though for that to do what you need, let me test >>> that and report back. >> >> >> I think things should work for all sizes, if you add this patch and then add >> buffer_compress_chunk=32k or similar to your job file. You can do that for >> smaller block sizes as well, fio will use the minimum of that chunk size or >> the write block size. >> >> -- >> Jens Axboe >> > > Applied the patch and added buffer_compress_chunk=32k and now it's > working for all block sizes. Thank you for the info and the patch! Perfect, thanks for reporting and followup testing. -- Jens Axboe