From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752635AbcGSIty (ORCPT ); Tue, 19 Jul 2016 04:49:54 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:54503 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066AbcGSItw (ORCPT ); Tue, 19 Jul 2016 04:49:52 -0400 Date: Tue, 19 Jul 2016 10:47:37 +0200 (CEST) From: Thomas Gleixner To: "Gaurav Jindal (Gaurav Jindal)" cc: "Sanjeev Yadav (Sanjeev Kumar Yadav)" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH]time: Optimize nohz idle enter In-Reply-To: <20160714120416.GB21099@gaurav.jindal@spreadtrum.com> Message-ID: References: <20160714120416.GB21099@gaurav.jindal@spreadtrum.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 14 Jul 2016, Gaurav Jindal (Gaurav Jindal) wrote: > > tick_nohz_start_idle is called before checking the condition if the idle tick > can be stopped. In case when can_stop_idle_tick returns 0, the function called > is of no use thus a extra call doing nothing. > > Shifting calling of function tick_nohz_start_idle inside the if condition makes > sure that corresponding operations are done only if idle tick can be actually > stopped. Observance for 1 minute on arm64 architecture shows that shifting code > can prevent 1.5% of extra calls thus optimizing the idle call sequence. Nice. > Signed-off-by: gaurav jindal > Signed-off-by: sanjeev yadav This SOB chain is wrong. Sanjeev did not send the patch and is not the author. Please clarify. Thanks, tglx