From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1172440AbdDXOY7 (ORCPT ); Mon, 24 Apr 2017 10:24:59 -0400 Received: from cmta18.telus.net ([209.171.16.91]:47346 "EHLO cmta18.telus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1171939AbdDXOYx (ORCPT ); Mon, 24 Apr 2017 10:24:53 -0400 X-Authority-Analysis: v=2.2 cv=ZfTyDodA c=1 sm=1 tr=0 a=zJWegnE7BH9C0Gl4FFgQyA==:117 a=zJWegnE7BH9C0Gl4FFgQyA==:17 a=Pyq9K9CWowscuQLKlpiwfMBGOR0=:19 a=IkcTkHD0fZMA:10 a=aatUQebYAAAA:8 a=VwQbUJbxAAAA:8 a=WGzSXS_7B4l8hDdoM74A:9 a=7Zwj6sZBwVKJAoWSPKxL6X1jA+E=:19 a=QEXdDO2ut3YA:10 a=7715FyvI7WU-l6oqrZBK:22 a=AjGcO6oz07-iQ99wixmX:22 From: "Doug Smythies" To: "'Srinivas Pandruvada'" , "'Rafael J. Wysocki'" Cc: "'Rafael J. Wysocki'" , "'Mel Gorman'" , "'Rafael Wysocki'" , "=?utf-8?Q?'J=C3=B6rg_Otte'?=" , "'Linux Kernel Mailing List'" , "'Linux PM'" , "Doug Smythies" References: <20170410084117.rjh3mtdx7hd2i5ze@techsingularity.net> <000a01d2b9e6$393afef0$abb0fcd0$@net> <000301d2bb31$c0037790$400a66b0$@net> <000501d2bc46$ad4b1fc0$07e15f40$@net> 2Sh4dt8AXIBJV2Sh6dNtdh In-Reply-To: 2Sh4dt8AXIBJV2Sh6dNtdh Subject: RE: Performance of low-cpu utilisation benchmark regressed severely since 4.6 Date: Mon, 24 Apr 2017 07:24:31 -0700 Message-ID: <000001d2bd06$7f29b960$7d7d2c20$@net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AdK8mR41+J6mZ7b1T6eGDIQ51QrnoQAaUyIA Content-Language: en-ca X-CMAE-Envelope: MS4wfEXTbuvL2dkTrgQ81R0WOz+tdxlCPP7AxZ2QLpJZtAsoJSsrVTvfUKe6bYaibmCf4gksAiVM74slvP2GyEuoLwYxNFvgWHWNggyCtN4TH4J/18ng0sZB I2j//lYas0TK9O1k1sgAmZciV2dCnPU+JIobWA+aJjSc5EHCriC0Z/kAZwH8HEPww7VHnxnmZizHDFxlynKGBwqKqYxPhNCLWYhuFo0Mj3vTscLN0j7ueIGO 9ZrmQIAKAyoFKrzUgLRfBeMtyNSEAm2d9o2lFwiydFwXRN4UxmxvK7kbEcmzT08bxGK9HiZ4S7jh3Du7VnTmquP70fWrq2TGGUy1CG6Wq4JY/SEn4TDSYp0U culBTmFwKGLVe5VnCgMQ7Axez2t/P2URVCWAWhaXJjuIVqQXEIyUioZ/V3AXPHCl2ax2t1QV146gwR7YIod/AhaSkG2+ahpPvnr9rLyDCACU6WTRDR8= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017.04.23 18:23 Srinivas Pandruvada wrote: > On Mon, 2017-04-24 at 02:59 +0200, Rafael J. Wysocki wrote: >> On Sun, Apr 23, 2017 at 5:31 PM, Doug Smythies wrote: >>> It looks like the cost is mostly related to moving the load from >>> one CPU to >>> another and waiting for the new one to ramp up then. > Last time when we analyzed Mel's result last year this was the > conclusion. The problem was more apparent on systems with per core P- > state. ?? I have never seen this particular use case before. Unless I have looked the wrong thing, Mel's issue last year was a different use case. ...[cut]... >>>> We can do one more trick I forgot about. Namely, if we are about >>>> to increase >>>> the P-state, we can jump to the average between the target and >>>> the max >>>> instead of just the target, like in the appended patch (on top of >>>> linux-next). >>>> >>>> That will make the P-state selection really aggressive, so costly >>>> energetically, >>>> but it shoud small jumps of the average load above 0 to case big >>>> jumps of >>>> the target P-state. >>> I'm already seeing the energy costs of some of this stuff. >>> 3050.2 Seconds. >> Is this with or without reducing the sampling interval? It was without reducing the sample interval. So, it was the branch you referred us to the other day: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next with your patch (now deleted from this thread) applied. ...[cut]... >> Anyway, your results are somewhat counter-intuitive. >> Would it be possible to run this workload with the linux-next branch >> and the schedutil governor and see if the patch at >> https://patchwork.kernel.org/patch/9671829/ makes any difference? git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next Plus that patch is in progress. ... Doug