From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938960AbcJXNNk (ORCPT ); Mon, 24 Oct 2016 09:13:40 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:48201 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932934AbcJXNNj (ORCPT ); Mon, 24 Oct 2016 09:13:39 -0400 From: "Rafael J. Wysocki" To: Srinivas Pandruvada , Linux PM list Cc: Linux Kernel Mailing List Subject: [PATCH] cpufreq: intel_pstate: Always set max P-state in performance mode Date: Mon, 24 Oct 2016 15:20:39 +0200 Message-ID: <1490845.P5jEmYeGuo@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.8.0-rc2+; KDE/4.11.5; x86_64; ; ) 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 From: Rafael J. Wysocki The only times when intel_pstate checks the policy set for a given CPU is the initialization of that CPU and updates of its settings from cpufreq leading to intel_pstate_set_policy() invocatios. That is insufficient, however, because intel_pstate uses the same P-state selection function for all CPUs regardless of the policy setting for each of them and the P-state limits are shared between them. Thus if the policy is set to "performance" for a particular CPU, it may not behave as expected if the cpufreq settings are changed subsequently for another CPU. That can be easily demonstrated by writing "performance" to scaling_governor for all CPUs and then switching it to "powersave" for one of them in which case all of the CPUs will behave as though their scaling_governor were "powersave" (even though the policy still appears to be "performance" for the remaining CPUs). Fix this problem by modifying intel_pstate_adjust_busy_pstate() to always set the P-state to the maximum allowed by the current limits if the policy is set to "performance" for the given CPU. Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -179,6 +179,7 @@ struct _pid { /** * struct cpudata - Per CPU instance data storage * @cpu: CPU number for this instance data + * @policy: CPUFreq policy value * @update_util: CPUFreq utility callback information * @update_util_set: CPUFreq utility callback is set * @iowait_boost: iowait-related boost fraction @@ -201,6 +202,7 @@ struct _pid { struct cpudata { int cpu; + unsigned int policy; struct update_util_data update_util; bool update_util_set; @@ -1331,7 +1333,8 @@ static inline void intel_pstate_adjust_b from = cpu->pstate.current_pstate; - target_pstate = pstate_funcs.get_target_pstate(cpu); + target_pstate = cpu->policy == CPUFREQ_POLICY_PERFORMANCE ? + cpu->pstate.turbo_pstate : pstate_funcs.get_target_pstate(cpu); intel_pstate_update_pstate(cpu, target_pstate); @@ -1498,6 +1501,8 @@ static int intel_pstate_set_policy(struc policy->cpuinfo.max_freq, policy->max); cpu = all_cpu_data[policy->cpu]; + cpu->policy = policy->policy; + if (cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate && policy->max < policy->cpuinfo.max_freq && policy->max > cpu->pstate.max_pstate * cpu->pstate.scaling) { @@ -1505,7 +1510,7 @@ static int intel_pstate_set_policy(struc policy->max = policy->cpuinfo.max_freq; } - if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { + if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) { limits = &performance_limits; if (policy->max >= policy->cpuinfo.max_freq) { pr_debug("set performance\n"); @@ -1541,7 +1546,7 @@ static int intel_pstate_set_policy(struc limits->max_perf = round_up(limits->max_perf, FRAC_BITS); out: - if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { + if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) { /* * NOHZ_FULL CPUs need this as the governor callback may not * be invoked on them.