From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Subject: Re: [PATCH] cpufreq, intel_pstate, Fix intel_pstate powersave min_perf_pct value Date: Wed, 14 Oct 2015 19:59:38 -0400 Message-ID: <561EEC6A.7000904@redhat.com> References: <1444822919-14650-1-git-send-email-prarit@redhat.com> <20151014140957.36523ea9@kcaccard-desk.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43770 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751098AbbJNX7k (ORCPT ); Wed, 14 Oct 2015 19:59:40 -0400 In-Reply-To: <20151014140957.36523ea9@kcaccard-desk.amr.corp.intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Kristen Carlson Accardi Cc: linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Viresh Kumar , linux-pm@vger.kernel.org, Doug Smythies On 10/14/2015 05:09 PM, Kristen Carlson Accardi wrote: > On Wed, 14 Oct 2015 07:41:59 -0400 > Prarit Bhargava wrote: > >> On systems that initialize the intel_pstate driver with the performance >> governor, and then switch to the powersave governor will not transition to >> lower cpu frequencies until /sys/devices/system/cpu/intel_pstate/min_perf_pct >> is set to a low value. >> >> The behavior of governor switching changed after commit a04759924e25 >> ("[cpufreq] intel_pstate: honor user space min_perf_pct override on >> resume"). The commit introduced tracking of performance percentage >> changes via sysfs in order to restore userspace changes during >> suspend/resume. The problem occurs because the global values of the newly >> introduced max_sysfs_pct and min_sysfs_pct are not lowered on the governor >> change and this causes the powersave governor to inherit the performance >> governor's settings. >> >> A simple change would have been to reset max_sysfs_pct to 100 and >> min_sysfs_pct to 0 on a governor change, which fixes the problem with >> governor switching. However, since we cannot break userspace[1] the fix >> is now to give each governor its own limits storage area so that governor >> specific changes are tracked. >> >> I successfully tested this by booting with both the performance governor >> and the powersave governor by default, and switching between the two >> governors (while monitoring /sys/devices/system/cpu/intel_pstate/ values, >> and looking at the output of cpupower frequency-info). Suspend/Resume >> testing was performed by Doug Smythies. >> >> [1] Systems which suspend/resume using the unmaintained pm-utils package >> will always transition to the performance governor before the suspend and >> after the resume. This means a system using the powersave governor will >> go from powersave to performance, then suspend/resume, performance to >> powersave. The simple change during governor changes would have been >> overwritten when the governor changed before and after the suspend/resume. >> I have submitted https://bugzilla.redhat.com/show_bug.cgi?id=1271225 >> against Fedora to remove the 94cpufreq file that causes the problem. It >> should be noted that pm-utils is obsoleted with newer versions of systemd. >> >> Cc: Kristen Carlson Accardi >> Cc: "Rafael J. Wysocki" >> Cc: Viresh Kumar >> Cc: linux-pm@vger.kernel.org >> Cc: Doug Smythies >> Signed-off-by: Prarit Bhargava > > Acked-by: Kristen Carlson Accardi > > BTW - I think I can see an issue here with HWP enabled systems. It > looks to me like the hwp settings will not be programmed correctly > during a governor switch. This probably needs to be addressed in a > separate patch. > Oh, I see it now too. I'll get to that in another patch. Thanks for pointing that out Kristen. P. >> --- >> drivers/cpufreq/intel_pstate.c | 120 +++++++++++++++++++++++++--------------- >> 1 file changed, 75 insertions(+), 45 deletions(-) >> >> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c >> index 3af9dd7..78b4be5 100644 >> --- a/drivers/cpufreq/intel_pstate.c >> +++ b/drivers/cpufreq/intel_pstate.c >> @@ -156,7 +156,20 @@ struct perf_limits { >> int min_sysfs_pct; >> }; >> >> -static struct perf_limits limits = { >> +static struct perf_limits performance_limits = { >> + .no_turbo = 0, >> + .turbo_disabled = 0, >> + .max_perf_pct = 100, >> + .max_perf = int_tofp(1), >> + .min_perf_pct = 100, >> + .min_perf = int_tofp(1), >> + .max_policy_pct = 100, >> + .max_sysfs_pct = 100, >> + .min_policy_pct = 0, >> + .min_sysfs_pct = 0, >> +}; >> + >> +static struct perf_limits powersave_limits = { >> .no_turbo = 0, >> .turbo_disabled = 0, >> .max_perf_pct = 100, >> @@ -169,6 +182,12 @@ static struct perf_limits limits = { >> .min_sysfs_pct = 0, >> }; >> >> +#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE >> +static struct perf_limits *limits = &performance_limits; >> +#else >> +static struct perf_limits *limits = &powersave_limits; >> +#endif >> + >> static inline void pid_reset(struct _pid *pid, int setpoint, int busy, >> int deadband, int integral) { >> pid->setpoint = setpoint; >> @@ -255,7 +274,7 @@ static inline void update_turbo_state(void) >> >> cpu = all_cpu_data[0]; >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_en); >> - limits.turbo_disabled = >> + limits->turbo_disabled = >> (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE || >> cpu->pstate.max_pstate == cpu->pstate.turbo_pstate); >> } >> @@ -274,14 +293,14 @@ static void intel_pstate_hwp_set(void) >> >> for_each_online_cpu(cpu) { >> rdmsrl_on_cpu(cpu, MSR_HWP_REQUEST, &value); >> - adj_range = limits.min_perf_pct * range / 100; >> + adj_range = limits->min_perf_pct * range / 100; >> min = hw_min + adj_range; >> value &= ~HWP_MIN_PERF(~0L); >> value |= HWP_MIN_PERF(min); >> >> - adj_range = limits.max_perf_pct * range / 100; >> + adj_range = limits->max_perf_pct * range / 100; >> max = hw_min + adj_range; >> - if (limits.no_turbo) { >> + if (limits->no_turbo) { >> hw_max = HWP_GUARANTEED_PERF(cap); >> if (hw_max < max) >> max = hw_max; >> @@ -350,7 +369,7 @@ static void __init intel_pstate_debug_expose_params(void) >> static ssize_t show_##file_name \ >> (struct kobject *kobj, struct attribute *attr, char *buf) \ >> { \ >> - return sprintf(buf, "%u\n", limits.object); \ >> + return sprintf(buf, "%u\n", limits->object); \ >> } >> >> static ssize_t show_turbo_pct(struct kobject *kobj, >> @@ -386,10 +405,10 @@ static ssize_t show_no_turbo(struct kobject *kobj, >> ssize_t ret; >> >> update_turbo_state(); >> - if (limits.turbo_disabled) >> - ret = sprintf(buf, "%u\n", limits.turbo_disabled); >> + if (limits->turbo_disabled) >> + ret = sprintf(buf, "%u\n", limits->turbo_disabled); >> else >> - ret = sprintf(buf, "%u\n", limits.no_turbo); >> + ret = sprintf(buf, "%u\n", limits->no_turbo); >> >> return ret; >> } >> @@ -405,12 +424,12 @@ static ssize_t store_no_turbo(struct kobject *a, struct attribute *b, >> return -EINVAL; >> >> update_turbo_state(); >> - if (limits.turbo_disabled) { >> + if (limits->turbo_disabled) { >> pr_warn("intel_pstate: Turbo disabled by BIOS or unavailable on processor\n"); >> return -EPERM; >> } >> >> - limits.no_turbo = clamp_t(int, input, 0, 1); >> + limits->no_turbo = clamp_t(int, input, 0, 1); >> >> if (hwp_active) >> intel_pstate_hwp_set(); >> @@ -428,11 +447,15 @@ static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b, >> if (ret != 1) >> return -EINVAL; >> >> - limits.max_sysfs_pct = clamp_t(int, input, 0 , 100); >> - limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); >> - limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); >> - limits.max_perf_pct = max(limits.min_perf_pct, limits.max_perf_pct); >> - limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); >> + limits->max_sysfs_pct = clamp_t(int, input, 0 , 100); >> + limits->max_perf_pct = min(limits->max_policy_pct, >> + limits->max_sysfs_pct); >> + limits->max_perf_pct = max(limits->min_policy_pct, >> + limits->max_perf_pct); >> + limits->max_perf_pct = max(limits->min_perf_pct, >> + limits->max_perf_pct); >> + limits->max_perf = div_fp(int_tofp(limits->max_perf_pct), >> + int_tofp(100)); >> >> if (hwp_active) >> intel_pstate_hwp_set(); >> @@ -449,11 +472,15 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b, >> if (ret != 1) >> return -EINVAL; >> >> - limits.min_sysfs_pct = clamp_t(int, input, 0 , 100); >> - limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); >> - limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); >> - limits.min_perf_pct = min(limits.max_perf_pct, limits.min_perf_pct); >> - limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); >> + limits->min_sysfs_pct = clamp_t(int, input, 0 , 100); >> + limits->min_perf_pct = max(limits->min_policy_pct, >> + limits->min_sysfs_pct); >> + limits->min_perf_pct = min(limits->max_policy_pct, >> + limits->min_perf_pct); >> + limits->min_perf_pct = min(limits->max_perf_pct, >> + limits->min_perf_pct); >> + limits->min_perf = div_fp(int_tofp(limits->min_perf_pct), >> + int_tofp(100)); >> >> if (hwp_active) >> intel_pstate_hwp_set(); >> @@ -533,7 +560,7 @@ static void byt_set_pstate(struct cpudata *cpudata, int pstate) >> u32 vid; >> >> val = (u64)pstate << 8; >> - if (limits.no_turbo && !limits.turbo_disabled) >> + if (limits->no_turbo && !limits->turbo_disabled) >> val |= (u64)1 << 32; >> >> vid_fp = cpudata->vid.min + mul_fp( >> @@ -622,7 +649,7 @@ static void core_set_pstate(struct cpudata *cpudata, int pstate) >> u64 val; >> >> val = (u64)pstate << 8; >> - if (limits.no_turbo && !limits.turbo_disabled) >> + if (limits->no_turbo && !limits->turbo_disabled) >> val |= (u64)1 << 32; >> >> wrmsrl_on_cpu(cpudata->cpu, MSR_IA32_PERF_CTL, val); >> @@ -702,7 +729,7 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max) >> int max_perf_adj; >> int min_perf; >> >> - if (limits.no_turbo || limits.turbo_disabled) >> + if (limits->no_turbo || limits->turbo_disabled) >> max_perf = cpu->pstate.max_pstate; >> >> /* >> @@ -710,11 +737,11 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max) >> * policy, or by cpu specific default values determined through >> * experimentation. >> */ >> - max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf)); >> + max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits->max_perf)); >> *max = clamp_t(int, max_perf_adj, >> cpu->pstate.min_pstate, cpu->pstate.turbo_pstate); >> >> - min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits.min_perf)); >> + min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits->min_perf)); >> *min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf); >> } >> >> @@ -988,32 +1015,35 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) >> >> if (policy->policy == CPUFREQ_POLICY_PERFORMANCE && >> policy->max >= policy->cpuinfo.max_freq) { >> - limits.min_policy_pct = 100; >> - limits.min_perf_pct = 100; >> - limits.min_perf = int_tofp(1); >> - limits.max_policy_pct = 100; >> - limits.max_perf_pct = 100; >> - limits.max_perf = int_tofp(1); >> - limits.no_turbo = 0; >> + pr_debug("intel_pstate: set performance\n"); >> + limits = &performance_limits; >> return 0; >> } >> >> - limits.min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; >> - limits.min_policy_pct = clamp_t(int, limits.min_policy_pct, 0 , 100); >> - limits.max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; >> - limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100); >> + pr_debug("intel_pstate: set powersave\n"); >> + limits = &powersave_limits; >> + limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; >> + limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100); >> + limits->max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; >> + limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100); >> >> /* Normalize user input to [min_policy_pct, max_policy_pct] */ >> - limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); >> - limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); >> - limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); >> - limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); >> + limits->min_perf_pct = max(limits->min_policy_pct, >> + limits->min_sysfs_pct); >> + limits->min_perf_pct = min(limits->max_policy_pct, >> + limits->min_perf_pct); >> + limits->max_perf_pct = min(limits->max_policy_pct, >> + limits->max_sysfs_pct); >> + limits->max_perf_pct = max(limits->min_policy_pct, >> + limits->max_perf_pct); >> >> /* Make sure min_perf_pct <= max_perf_pct */ >> - limits.min_perf_pct = min(limits.max_perf_pct, limits.min_perf_pct); >> + limits->min_perf_pct = min(limits->max_perf_pct, limits->min_perf_pct); >> >> - limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); >> - limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); >> + limits->min_perf = div_fp(int_tofp(limits->min_perf_pct), >> + int_tofp(100)); >> + limits->max_perf = div_fp(int_tofp(limits->max_perf_pct), >> + int_tofp(100)); >> >> if (hwp_active) >> intel_pstate_hwp_set(); >> @@ -1057,7 +1087,7 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy) >> >> cpu = all_cpu_data[policy->cpu]; >> >> - if (limits.min_perf_pct == 100 && limits.max_perf_pct == 100) >> + if (limits->min_perf_pct == 100 && limits->max_perf_pct == 100) >> policy->policy = CPUFREQ_POLICY_PERFORMANCE; >> else >> policy->policy = CPUFREQ_POLICY_POWERSAVE; >