From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932317AbcDDRAS (ORCPT ); Mon, 4 Apr 2016 13:00:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49934 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754358AbcDDRAQ (ORCPT ); Mon, 4 Apr 2016 13:00:16 -0400 From: Bandan Das To: "Michael Rapoport" Cc: jiangshanlai@gmail.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, Tejun Heo Subject: Re: [RFC PATCH 0/4] cgroup aware workqueues References: <1458339291-4093-1-git-send-email-bsd@redhat.com> <201603210758.u2L7wiY9003907@d06av07.portsmouth.uk.ibm.com> <20160330170419.GG7822@mtj.duckdns.org> <201603310617.u2V6HIkt008006@d06av12.portsmouth.uk.ibm.com> <20160331171435.GD24661@htj.duckdns.org> <201604031043.u33AhpSF023771@d06av06.portsmouth.uk.ibm.com> Date: Mon, 04 Apr 2016 13:00:12 -0400 In-Reply-To: <201604031043.u33AhpSF023771@d06av06.portsmouth.uk.ibm.com> (Michael Rapoport's message of "Sun, 3 Apr 2016 13:43:46 +0300") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ... >> There have been discussions about this in the past and iirc, most people > agree >> about not going the byos* route. But I am still all for such a proposal > and if >> it's good/clean enough, I think we can definitely tear down what we have > and >> throw it away! The I/O scheduling part is intrusive enough that even the > current >> code base has to be changed quite a bit. > > The "byos" route seems more promising with respect to possible performance > gains, but it will definitely add complexity, and I cannot say if the > added complexity will be worth performance improvements. > > Meanwhile, I'd suggest we better understand what causes regression with > your current patches and maybe then we'll be smarter to get to the right > direction. :) > Agreed, let's try to understand the cause of the "underperformance" with wqs. I disabled WQ_CGROUPS that effectively disables my changes and I can still consistently reproduce the lower numbers. >> *byos = bring your own scheduling ;) >> >> > Thanks. > > -- > Sincerely yours, > Mike. > > [1] https://lwn.net/Articles/650857/