Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932917Ab3FFKKS (ORCPT ); Thu, 6 Jun 2013 06:10:18 -0400 Received: from mail-ob0-f182.google.com ([209.85.214.182]:55321 "EHLO mail-ob0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932588Ab3FFKKO (ORCPT ); Thu, 6 Jun 2013 06:10:14 -0400 MIME-Version: 1.0 In-Reply-To: <20130606100138.GC21181@pd.tnic> References: <51AF60D5.3080605@semaphore.gr> <20130605161703.GA29958@pd.tnic> <51AF71B6.6030408@semaphore.gr> <105446113.ZumbZWCbSi@vostro.rjw.lan> <20130606100138.GC21181@pd.tnic> Date: Thu, 6 Jun 2013 15:40:13 +0530 Message-ID: Subject: Re: [PATCH v3 1/3] cpufreq: ondemand: Change the calculation of target frequency From: Viresh Kumar To: Borislav Petkov Cc: "Rafael J. Wysocki" , Stratos Karafotis , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-pm@vger.kernel.org, cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1335 Lines: 40 On 6 June 2013 15:31, Borislav Petkov wrote: > Hold on, you say above "easily saturate minimum frequency and lead the > CPU to max". I read this as we jump straight to max P-state where we > even boost. Probably he meant: "At lowest levels of frequencies, a small load on system may look like a huge one. like: 20-30% load on max freq can be 95% load on min freq. And so we jump to max freq even for this load and return back pretty quickly as this load doesn't sustain for longer. over that we wait for load to go over up_threshold to increase freq." > "CPU to max" finishes the work faster than middle frequencies, if you're > CPU-bound. He isn't removing this feature at all. Current code is: if (load > up_threshold) goto maxfreq. else don't increase freq, maybe decrease it in steps What he is doing is: if (load > up_threshold) goto maxfreq. else increase/decrease freq based on current load. So, if up_threshold is 95 and load remains < 95, his patch will give significant improvement both power & performance wise. Else, it shouldn't decrease it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/