From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A788C54E4A for ; Tue, 12 May 2020 13:36:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56630206DD for ; Tue, 12 May 2020 13:36:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729982AbgELNgP convert rfc822-to-8bit (ORCPT ); Tue, 12 May 2020 09:36:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:44760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729568AbgELNgO (ORCPT ); Tue, 12 May 2020 09:36:14 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC137206D3; Tue, 12 May 2020 13:36:13 +0000 (UTC) Date: Tue, 12 May 2020 09:36:12 -0400 From: Steven Rostedt To: Elana Copperman Cc: linux-rt-users , Thomas Gleixner , "Vladimir Kondratiev (Mobileye)" <63dc4b5d-c467-4bfb-bce5-74485907c850@intel.mail.onmicrosoft.com> Subject: Re: cgroups CPU time management + PREEMPT_RT Message-ID: <20200512093612.416899e1@gandalf.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Tue, 12 May 2020 13:30:27 +0000 Elana Copperman wrote: > Hi, can you help to clarify if there is any implementation support or > evidence on configuring cgroups CPU time allocations for RT tasks in > conjunction with the PREEMPT_RT patch? What exactly are you trying to do with cgroups CPU time allocations, and what is the problem you are seeing with the PREEMPT_RT patch with them? I'm assuming you are using the 5.6-rt kernel. -- Steve > > Or are the two requirements contradictory in essence and not jointly > feasible? > > Thanks > > Elana and Vladimir > > > > > From: Elana Copperman > > Sent: Thursday, May 7, 2020 10:08 PM > > To: linux-rt-users ; Vladimir Kondratiev > (Mobileye) > <63dc4b5d-c467-4bfb-bce5-74485907c850@intel.mail.onmicrosoft.com> > > Subject: RE: cgroups CPU time management + PREEMPT_RT > >   > > > Hi, > > We are new to the mailing list, and new to PREEMPT_RT. > > We are working on a project with a safety requirement to configure > cgroups for resource management, as well as functional requirement for > deployment of PREEMPT_RT patch. > > cgroups in general can be used in this context, in particular for > managing resources such as memory; and even for managing CPU time for > non-RT tasks.  > > > However, we do see a potential problem with RT tasks, and how the CPU > controller would work with the RT scheduling. > > There is some obvious concern here, and this seems to be backed by what I > find online regarding this question. > > > > Can you help us to clarify what is the current state of implementation, > and if there is any support for cgroup CPU controller configuration to > work effectively with PREEMPT_RT for RT tasks?  > > > Thanks > > Elana > > > > >