From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753237AbcERMyJ (ORCPT ); Wed, 18 May 2016 08:54:09 -0400 Received: from e28smtp07.in.ibm.com ([125.16.236.7]:46754 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751992AbcERMyG (ORCPT ); Wed, 18 May 2016 08:54:06 -0400 X-IBM-Helo: d28dlp03.in.ibm.com X-IBM-MailFrom: shilpa.bhat@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-pm@vger.kernel.org From: Shilpasri G Bhat To: rjw@rjwysocki.net Cc: viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, ego@linux.vnet.ibm.com, shreyas@linux.vnet.ibm.com, akshay.adiga@linux.vnet.ibm.com, linuxppc-dev@ozlabs.org, Shilpasri G Bhat Subject: [RFC PATCH] cpufreq: powernv: Add fast_switch callback Date: Wed, 18 May 2016 18:23:40 +0530 Message-Id: <1463576020-18597-2-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1463576020-18597-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> References: <1463576020-18597-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16051812-0025-0000-0000-00000C5A3E2D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add fast_switch driver callback to support frequency update in interrupt context while using schedutil governor. Changing frequency in interrupt context will remove the jitter on the workloads which can be seen when a kworker thread is used for the changing the frequency. Signed-off-by: Shilpasri G Bhat --- drivers/cpufreq/powernv-cpufreq.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 54c4536..4553eb6 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -678,6 +678,8 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy) for (i = 0; i < threads_per_core; i++) cpumask_set_cpu(base + i, policy->cpus); + policy->fast_switch_possible = true; + kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name); if (!kn) { int ret; @@ -854,6 +856,24 @@ static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy) del_timer_sync(&gpstates->timer); } +static unsigned int powernv_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + int index; + struct powernv_smp_call_data freq_data; + + cpufreq_frequency_table_target(policy, policy->freq_table, + target_freq, + CPUFREQ_RELATION_C, &index); + if (index < 0 || index >= powernv_pstate_info.nr_pstates) + return CPUFREQ_ENTRY_INVALID; + freq_data.pstate_id = powernv_freqs[index].driver_data; + freq_data.gpstate_id = powernv_freqs[index].driver_data; + set_pstate(&freq_data); + + return pstate_id_to_freq(-index); +} + static struct cpufreq_driver powernv_cpufreq_driver = { .name = "powernv-cpufreq", .flags = CPUFREQ_CONST_LOOPS, @@ -861,6 +881,7 @@ static struct cpufreq_driver powernv_cpufreq_driver = { .exit = powernv_cpufreq_cpu_exit, .verify = cpufreq_generic_frequency_table_verify, .target_index = powernv_cpufreq_target_index, + .fast_switch = powernv_fast_switch, .get = powernv_cpufreq_get, .stop_cpu = powernv_cpufreq_stop_cpu, .attr = powernv_cpu_freq_attr, -- 1.9.3