From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753522AbaE3C1h (ORCPT ); Thu, 29 May 2014 22:27:37 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48450 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149AbaE3C1f (ORCPT ); Thu, 29 May 2014 22:27:35 -0400 Date: Thu, 29 May 2014 19:27:34 -0700 From: Greg Kroah-Hartman To: Johan Hovold Cc: Dirk Brandewie , Viresh Kumar , dirk.j.brandewie@intel.com, "Rafael J. Wysocki" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List , Doug Smythies , Yuyang Du , Stratos Karafotis Subject: Re: Performance regression in v3.14 Message-ID: <20140530022734.GC19080@kroah.com> References: <20140506163559.GA5308@localhost> <536A3EE9.5050409@intel.com> <20140521090051.GO21412@localhost> <20140528075945.GA21705@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140528075945.GA21705@localhost> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 28, 2014 at 09:59:45AM +0200, Johan Hovold wrote: > [ +CC: Greg, Doug, Stratos, Yuyang ] > > On Wed, May 21, 2014 at 11:00:51AM +0200, Johan Hovold wrote: > > On Wed, May 07, 2014 at 07:10:49AM -0700, Dirk Brandewie wrote: > > > On 05/06/2014 10:40 PM, Viresh Kumar wrote: > > > > Cc'ing Dirk who is taking care of intel-pstate driver. > > > > > > > > > > Thanks Viresh I had seen this thread. > > > > > > I am looking into it > > > > Any updates on this, Dirk? 3.14 is still basically unusable with the > > intel_pstate driver. > > > > Any fixes or workarounds posted elsewhere that I can apply in the > > meantime? > > Another week and still no reply, Dirk? > > I tried applying your (rejected) patch "intel_pstate: Remove C0 > tracking" posted here: > > https://lkml.org/lkml/2014/5/8/574 > > to v3.14.4 and it fixes the problem as expected. > > So we have a commit fcb6a15c2e7e ("intel_pstate: Take core C0 time into > account for core busy calculation") that went into v3.14-rc2 (and was > even marked for *stable*) that first broke Greg KH's system: > > https://lkml.org/lkml/2014/2/19/626 > > That was apparently fixed by e66c17683746 ("intel_pstate: Change > busy calculation to use fixed point math."), but still left v3.14 > basically unusable for lower-intensity workloads such as my > bash-completion example and other reported regressions: > > https://bugzilla.kernel.org/show_bug.cgi?id=75121 > > Sure there may be issues with v3.13 not hitting the lowest frequencies > but at least the system was *usable*. > > In my opinion there's really no other option than to restore the 3.13 > behaviour by effectively reverting fcb6a15c2e7e ("intel_pstate: Take > core C0 time into account for core busy calculation") until you have > figured out a way to take C0 into account without breaking things too > badly. Dirk has posted some patches, do they fix the problem for you? thanks, greg k-h