From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753627AbdL1NZG convert rfc822-to-8bit (ORCPT ); Thu, 28 Dec 2017 08:25:06 -0500 Received: from mout.gmx.net ([212.227.17.20]:55117 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751411AbdL1NZF (ORCPT ); Thu, 28 Dec 2017 08:25:05 -0500 Message-ID: <1514467413.6886.35.camel@gmx.de> Subject: Re: niced tasks on SMT system From: Mike Galbraith To: Pavel Machek , Thomas Gleixner , kernel list Cc: mingo@redhat.com, hpa@zytor.com, x86@kernel.org, peterz@infradead.org Date: Thu, 28 Dec 2017 14:23:33 +0100 In-Reply-To: <20171228121024.GA18152@amd> References: <20171228121024.GA18152@amd> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K0:2fVfdtwTpzGsmf8WlW+HuqzYjhc6ynn/Um/f4/KTL/sCo9s/WCr FfMc/YHxmE+E+fT4XkNyXGqgxKpqtWGi4hytENVcibmgu+cLEiHdzjb2Y46yAHn24T+Z/9Y uVMmPkRyWz2oOJw7o7+vmMDJQrrCCZX4lqOWIIJnk3g3zPAHJENcZi/7JeeZ/yj1CZMJy/e XDrgz4eVYCnMw0qg8peyg== X-UI-Out-Filterresults: notjunk:1;V01:K0:w2NvxjlvzDg=:IGfPWBcJNSyWYuxVs0YjC2 r3FBYk67ElKewOOQOpZ1O58l7IcOrLdl8OEwGjFhtIOvDzbo8biFCafM2VPAghCTM+nsknSEg PEen61geD12RHuAR5aiy7YoLBhVVXdv2i6vyhD33dMvDlJFUAcqOo1AXxfep2Q/tEbjLTGvFE z3QQIZfClC+FP7yhlIEmDWe0rmeMept+BFzKgDb+toNr7uAxrJkSS76aQkees3yYEWjFHMUfQ 8yhv4jKAD5WVvicufgiAysDNeml9GbI3EO9owDl5X1QRbx6lgIZw23aD2YtpTEcVArlVhQRRD eZGo+9To+gW8Swj0NuoPuOGMOY2QH9tMtqQiqlu92alHghWocaIP5dW2iGkbroAlsnJzLcjuv S+rBjK76EurC0boaR+2eUYJf20vLcI8Lqqywx0HWEgkrNRNRHbtEzJLC1VtLWa2ijlADdWHdp gbEIk9FuF0rPhdHB/57L80EYgVIJK5opa8UfwFk2L4toF925mpuS4l9R+C8eqTvnF/RTm7Lc3 cUIOxV7brZRDeoomMRvmhSbRvBCCUwAYcsTVDXnVUA+2Z988+6EKvMI59lRJ3FDftKtXzpXQ9 Ib1EBCZ7u1Xj7jBArFCq9S6ggtJzrPQ5dZQeknAhT/DywDjpYLbj2/H5Hg6yDMPaI9hxfHWnt J0S5GPkh3xk3zT0I031s065VXtmd9c8SGUeknWlBkK/1G8WPyTJBzWy8qdYxyYJvliGPTTUD0 c+hPXXW4A8yqiDGklxCMyKUbBVkhp9D+A50ema792c0y7sHljry1s36vZPZa5BJ1hdOdu0xwF if0AVz2peweewyFT3WGFlUQbpBFrYpcmGTDEPbk2GkQ2L+rFXnqaYsXb2a0+QQMXcCJbjFl Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2017-12-28 at 13:10 +0100, Pavel Machek wrote: > Hi! > > Ok, so I'm compiling, and I'd like to run a flight simulator. > > Flightgear normally does 20fps on my system... kinda low but playable. > > I have reniced make -j 5 fo kernel running. Scheduler gives 100% of > one of CPUs to Flightgear (good), but the smt sibling is used by the > compilation, and I'm down to 9 fps. Not good. > > Even with single-threaded make, I have 10-13fps. > > Is there way to learn which CPUs are SMT siblings? cat /sys/devices/system/cpu/cpu{N}/topology/thread_siblings > Is there way to disable SMT during runtime? You could offline them, but wouldn't it be better to tell each which CPUs they can use, or perhaps partition your box with cpusets? > Can I do something to improve Flightgear performance and still do > compilation? Sure, run everything associated with your game as RT, and everything not game gets the leftover cycles.  If there are none, box will  throttle RT to save itself from it's psycho :) driver and you'll know that you need a bigger box. (it's likely your phone) Oh yeah, echo NO_RT_RUNTIME_SHARE > /sys/kernel/debug/sched_features before you try that, otherwise the throttle won't help. -Mike