From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3r8vKB3KLwzDqCK for ; Wed, 18 May 2016 22:54:06 +1000 (AEST) Received: from e28smtp07.in.ibm.com (e28smtp07.in.ibm.com [125.16.236.7]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3r8vK94NH5z9t6B for ; Wed, 18 May 2016 22:54:05 +1000 (AEST) Received: from localhost by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 May 2016 18:24:02 +0530 Received: from d28relay08.in.ibm.com (d28relay08.in.ibm.com [9.184.220.159]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id C1365125805B for ; Wed, 18 May 2016 18:26:12 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay08.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u4ICrxFQ25166066 for ; Wed, 18 May 2016 18:23:59 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u4ICrwVl011479 for ; Wed, 18 May 2016 18:23:59 +0530 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> 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> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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