Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754298AbcJDTOc (ORCPT ); Tue, 4 Oct 2016 15:14:32 -0400 Received: from mail-yw0-f179.google.com ([209.85.161.179]:35141 "EHLO mail-yw0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671AbcJDTOa (ORCPT ); Tue, 4 Oct 2016 15:14:30 -0400 Date: Tue, 4 Oct 2016 15:14:27 -0400 From: Tejun Heo To: Paolo Valente Cc: Shaohua Li , Vivek Goyal , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Jens Axboe , Kernel-team@fb.com, jmoyer@redhat.com, Mark Brown , Linus Walleij , Ulf Hansson Subject: Re: [PATCH V3 00/11] block-throttle: add .high limit Message-ID: <20161004191427.GG4205@htj.duckdns.org> References: <20161004132805.GB28808@redhat.com> <20161004155616.GB4205@htj.duckdns.org> <20161004162759.GD4205@htj.duckdns.org> <278BCC7B-ED58-4FDF-9243-FAFC3F862E4D@unimore.it> <20161004172852.GB73678@anikkar-mbp.local.dhcp.thefacebook.com> <20161004185413.GF4205@htj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 833 Lines: 22 Hello, Paolo. On Tue, Oct 04, 2016 at 09:02:47PM +0200, Paolo Valente wrote: > That's exactly what BFQ has succeeded in doing in all the tests > devised so far. Can you give me a concrete example for which I can > try with BFQ and with any other mechanism you deem better. If > you are right, numbers will just make your point. Hmm... I think we already discussed this but here's a really simple case. There are three unknown workloads A, B and C and we want to give A certain best-effort guarantees (let's say around 80% of the underlying device) whether A is sharing the device with B or C. I get that bfq can be a good compromise on most desktop workloads and behave reasonably well for some server workloads with the slice expiration mechanism but it really isn't an IO resource partitioning mechanism. Thanks. -- tejun