From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH V2 0/2] cpufreq: Use sorted frequency tables Date: Wed, 1 Jun 2016 16:09:53 +0530 Message-ID: Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:34929 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750697AbcFAKj7 (ORCPT ); Wed, 1 Jun 2016 06:39:59 -0400 Received: by mail-pf0-f169.google.com with SMTP id g64so13011577pfb.2 for ; Wed, 01 Jun 2016 03:39:59 -0700 (PDT) Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Rafael Wysocki Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, smuckle@linaro.org, Viresh Kumar Hi Guys, This work in inspired by some of the concerns raised by Steve in one of his patchset. Currently, the cpufreq drivers aren't required to provide a sorted list of frequencies to the cpufreq-core and so traversing that list match a target frequency is very inefficient. This is not bearable by, for example, the fast-switch path of schedutil governor and so we have moved the traversing logic local to the acpi-cpufreq driver for now. That is better handled in the core, but it has to be efficient first. OTOH, even for traditional governors without a fast-switch path, it would be much better to be able to traverse this table quickly. The ideal solution would be to keep a single *sorted* freq-table in struct cpufreq_policy. But there are few dependencies due to which it can't be done today (Hint: cpufreq drivers are abusing the 'index' passed to them, to refer to multiple arrays). And so for now, lets create a separate table local to the cpufreq-core *only*. This modifies the existing API cpufreq_frequency_table_target() to use the sorted table. Lightly tested on Exynos board, frequencies were getting selected as expected. V1->V2: - This optimizes cpufreq_frequency_table_target() instead of new APIs. - Is rebased over bleeding-edge + following cleanup series. [PATCH 0/8] cpufreq: cleanups and reorganization -- viresh Viresh Kumar (2): cpufreq: Store sorted frequency table cpufreq: Optimize cpufreq_frequency_table_target() drivers/cpufreq/acpi-cpufreq.c | 15 +-- drivers/cpufreq/cpufreq.c | 23 ++-- drivers/cpufreq/freq_table.c | 247 ++++++++++++++++++++++++++------------ drivers/cpufreq/s3c24xx-cpufreq.c | 13 +- include/linux/cpufreq.h | 23 +++- 5 files changed, 220 insertions(+), 101 deletions(-) -- 2.7.1.410.g6faf27b