From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934804AbcA1ILS (ORCPT ); Thu, 28 Jan 2016 03:11:18 -0500 Received: from e19.ny.us.ibm.com ([129.33.205.209]:40057 "EHLO e19.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934754AbcA1ILN (ORCPT ); Thu, 28 Jan 2016 03:11:13 -0500 X-IBM-Helo: d01dlp02.pok.ibm.com X-IBM-MailFrom: ego@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-pm@vger.kernel.org Date: Thu, 28 Jan 2016 13:41:03 +0530 From: Gautham R Shenoy To: Shilpasri G Bhat Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, pc@us.ibm.com, anton@samba.org, ego@linux.vnet.ibm.com, shreyas@linux.vnet.ibm.com, bsingharora@gmail.com, mpe@ellerman.id.au Subject: Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Message-ID: <20160128081103.GB13654@in.ibm.com> Reply-To: ego@linux.vnet.ibm.com References: <1453965941-7363-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> <1453965941-7363-4-git-send-email-shilpa.bhat@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453965941-7363-4-git-send-email-shilpa.bhat@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16012808-0057-0000-0000-000003430630 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 28, 2016 at 12:55:38PM +0530, Shilpasri G Bhat wrote: > cpu_to_chip_id() does a DT walk through to find out the chip id by > taking a contended device tree lock. This adds an unnecessary overhead > in a hot path. So instead of calling cpu_to_chip_id() everytime cache > the chip ids for all cores in the array 'core_to_chip_map' and use it > in the hotpath. > > Reported-by: Anton Blanchard > Signed-off-by: Shilpasri G Bhat Reviewed-by: Gautham R. Shenoy -- Thanks and Regards gautham.