From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753364AbcEDVOE (ORCPT ); Wed, 4 May 2016 17:14:04 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:45469 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752613AbcEDVOC (ORCPT ); Wed, 4 May 2016 17:14:02 -0400 From: "Rafael J. Wysocki" To: Akshay Adiga Cc: viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, ego@linux.vnet.ibm.com Subject: Re: [PATCH v3 0/2] cpufreq: powernv: Ramp-down global pstate slower than local-pstate Date: Wed, 04 May 2016 23:17:14 +0200 Message-ID: <2253617.134ktIcBZI@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.5.0-rc1+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1461059881-14434-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> References: <1461059881-14434-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, April 19, 2016 03:27:59 PM Akshay Adiga wrote: > The frequency transition latency from pmin to pmax is observed to be in few > millisecond granurality. And it usually happens to take a performance penalty > during sudden frequency rampup requests. > > This patch set solves this problem by using a chip-level entity called "global > pstates". Global pstate manages elements across other dependent core chiplets. > Typically, the element that needs to be managed is the voltage setting. > So by holding global pstates higher than local pstate for some amount of time > ( ~5 seconds) the subsequent rampups could be made faster. > > (1/2) patch removes the flag from cpufreq_policy->driver_data, so that it can > be used for tracking global pstates. > > (2/2) patch adds code for global pstate management. > - The iozone results with this patchset, shows improvements in almost all cases. > - YCSB workload on redis with various target operations per second shows > better MaxLatency with this patch. > > Changes from v1: > - Fixed coding style > - Added a routine to reset global_pstate_info instead of hacky memset > - Handled case where cpufreq_table_validate_and_show() fails > - changed int queue_gpstate_timer() to void queue_gpstate_timer() > > Changes from v2: > - dropped the unreated change. > > Akshay Adiga (1): > cpufreq: powernv: Ramp-down global pstate slower than local-pstate > > Shilpasri G Bhat (1): > cpufreq: powernv: Remove flag use-case of policy->driver_data > > drivers/cpufreq/powernv-cpufreq.c | 269 ++++++++++++++++++++++++++++++++++++-- > 1 file changed, 256 insertions(+), 13 deletions(-) Both [1-2/2] applied, thanks!