From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gautham R Shenoy Subject: Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Date: Thu, 28 Jan 2016 13:41:03 +0530 Message-ID: <20160128081103.GB13654@in.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> Reply-To: ego@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1453965941-7363-4-git-send-email-shilpa.bhat@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-pm@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