From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751359AbeDEIko (ORCPT ); Thu, 5 Apr 2018 04:40:44 -0400 Received: from mout.gmx.net ([212.227.17.21]:60635 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbeDEIkl (ORCPT ); Thu, 5 Apr 2018 04:40:41 -0400 Message-ID: <1522917620.5593.5.camel@gmx.de> Subject: Re: sched_rt_period_timer causing large latencies From: Mike Galbraith To: Peter Zijlstra , Nicholas Piggin Cc: Linux Kernel Mailing List , Steven Rostedt Date: Thu, 05 Apr 2018 10:40:20 +0200 In-Reply-To: <20180405082701.GL4082@hirez.programming.kicks-ass.net> References: <20180405091138.6ef14d15@roar.ozlabs.ibm.com> <20180405082701.GL4082@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.22.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:I8fw30LbV454QAB9F7XmdJTpiCpxLBJhdlwX1LR6TdYMF4o55Hr q3k0SB0+ts3WjpBdcaWBzVMlJlBue+oeJr51PONk8g+P4EgKrucYpn8GrP03UZGYqzNXzAP kCr+vWzqwfxYGvaPmHYUedAF/edlE48lU+mhRBKhZSyKriBg5VtcVj3TZgIty6RDAwRvuxV nVyK+zQzNupamRuTZeuRA== X-UI-Out-Filterresults: notjunk:1;V01:K0:D+PTt5r+c6Q=:SPDk165sfyY4abIkreQR04 e3JWX+LY7ba84IXEGdcysbslIfnR/+Zl9PHMrHKXaAryawhfc6rLGV23dpXU55tuMwSIFQtNc ZkbynIzgNM/MUnATTD4AijPs+27RMZBcQiyLQ5tos9Qv2CuM18LVRUXX4N+6r6bakoqZF5/Yu VnM4Zj/8N6DJsby6hhUOY2o9p3nxdTAu34MU97G2naujq41nX2wz5Xq45PRsL0DA89al3yPta GbcYRYmmkqDCnY5ziGIKa+p+60Yh8nyRd1qVTyT8DEYzv8xqemhQKBQEl7+tkg9vBn6BuGeaz bcp+E3hm9RwqUlRS7lKGrRv7xhdxVDRovRmdINB848v6oAHtxkE+hpsahgNorL6eA91WkbwdK /40yXMS9KGO/i7eilq1jFZHPX8DJagWho7rNaxvV47QQKtZgmKYNna3pllNLnq1+TydPy7lUK SPPppe0+ubcImcNVxWPG56yX3KHAqwPyLw1DnfNiQhxswMYybW2BOeJDs+Xzae7Uf5xb/cKEL 2tt3tsqq5ODRew8h7chnhkbnH1raw/e+0+55gKrieudtpyNgUQQ3KSk5CIPU2ROX3td5GvL/p OyRzW9XbMyadZinGSZhJQzqX2f2W+7TTxNM9eYcjCqPX8PTWD0QxrBU6s9wVHEMghfECyuKT9 osJQ06f73Ibb7tKqOYPeODOT2Z2HFDBX+MqUOVGPgKOXZF5M5bNWV3hEoEZGtOdPV7Hq0zNRN Zn//SgQf0k4q2f7JGnr6NQzwmGFyX40K+qYZUSy9937u3W4hU6Wvvlz3WRj9RGguEVypFyorv UVti3d/y7luBszPT8RDkw7IYFyM88GWCpp+WvMn0F2FNMg6/NM= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2018-04-05 at 10:27 +0200, Peter Zijlstra wrote: > On Thu, Apr 05, 2018 at 09:11:38AM +1000, Nicholas Piggin wrote: > > Hi, > > > > I'm seeing some pretty big latencies on a ~idle system when a CPU wakes > > out of a nohz idle. Looks like it's due to the taking a lot of remote > > locks and cache lines. irqoff trace: > > On RT I think we default RT_RUNTIME_SHARE to false, maybe we should do > the same for mainline. Probably. My very first enterprise encounter with the thing was it NOT saving a box from it's not so clever driver due to that. -Mike