From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kashyap Desai Subject: RE: Device or HBA level QD throttling creates randomness in sequetial workload Date: Mon, 24 Oct 2016 18:35:01 +0530 Message-ID: <1f7cec69e6e12b6baa8e7f180a8e41b3@mail.gmail.com> References: <97184c74229af78b0d97e6b8016af972@mail.gmail.com> <20161021213121.GA10030@vader.DHCP.thefacebook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-yb0-f178.google.com ([209.85.213.178]:34314 "EHLO mail-yb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936015AbcJXNO6 (ORCPT ); Mon, 24 Oct 2016 09:14:58 -0400 Received: by mail-yb0-f178.google.com with SMTP id f97so75107953ybi.1 for ; Mon, 24 Oct 2016 06:14:57 -0700 (PDT) In-Reply-To: <20161021213121.GA10030@vader.DHCP.thefacebook.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Omar Sandoval Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, axboe@kernel.dk, Christoph Hellwig , paolo.valente@linaro.org > > On Fri, Oct 21, 2016 at 05:43:35PM +0530, Kashyap Desai wrote: > > Hi - > > > > I found below conversation and it is on the same line as I wanted some > > input from mailing list. > > > > http://marc.info/?l=linux-kernel&m=147569860526197&w=2 > > > > I can do testing on any WIP item as Omar mentioned in above discussion. > > https://github.com/osandov/linux/tree/blk-mq-iosched I tried build kernel using this repo, but looks like it is not allowed to reboot due to some changes in layer. > > Are you using blk-mq for this disk? If not, then the work there won't affect you. YES. I am using blk-mq for my test. I also confirm if use_blk_mq is disable, Sequential work load issue is not seen and scheduling works well. > > > Is there any workaround/alternative in latest upstream kernel, if user > > wants to see limited penalty for Sequential Work load on HDD ? > > > > ` Kashyap > >