| Message ID | e789eceae3f32a66fff923daeb85b33b88f21fe1.1565161495.git.viresh.kumar@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [V4,1/2] cpufreq: schedutil: Don't skip freq update when limits change | expand |
On 2019.08.07 00:06 Viresh Kumar wrote: Thanks for your work on this. > Intel pstate driver exposes min_perf_pct and max_perf_pct sysfs files, > which can be used to force a limit on the min/max P state of the driver. > Though these files eventually control the min/max frequencies that the > CPUs will run at, they don't make a change to policy->min/max values. > > When the values of these files are changed (in passive mode of the > driver), it leads to calling ->limits() callback of the cpufreq > governors, like schedutil. On a call to it the governors shall > forcefully update the frequency to come within the limits. Since the > limits, i.e. policy->min/max, aren't updated by the driver, the > governors fails to get the target freq within limit and sometimes aborts > the update believing that the frequency is already set to the target > value. > > This patch implements the QoS supported frequency constraints to update > policy->min/max values whenever min_perf_pct or max_perf_pct files are > updated. This is only done for the passive mode as of now, as the driver > is already working fine in active mode. > > Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX") > Reported-by: Doug Smythies <dsmythies@telus.net> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Tested by: Doug Smythies <dsmythies@telus.net> Thermald seems to now be working O.K. for all the governors. I do note that if one sets /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq It seems to override subsequent attempts via /sys/devices/system/cpu/intel_pstate/max_perf_pct. Myself, I find this confusing. So the question becomes which one is the "master"? Example: # for file in /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq; do echo "2200000" > $file; done # cat /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq 2200000 2200000 2200000 2200000 2200000 2200000 2200000 2200000 root@s15:/home/doug/temp# cat /sys/devices/system/cpu/intel_pstate/max_perf_pct ... (Note: 50% = 1900000) root@s15:/home/doug/temp# cat /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq 1900000 1900000 1900000 1900000 1900000 1900000 1900000 1900000 root@s15:/home/doug/temp# echo 100 > /sys/devices/system/cpu/intel_pstate/max_perf_pct ... (Note: 50% = 3800000, and my expectation is 3.8 GHz below) root@s15:/home/doug/temp# cat /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq 2200000 2200000 2200000 2200000 2200000 2200000 2200000 2200000 Similarly for the minimum side of things: root@s15:/home/doug/temp# for file in /sys/devices/system/cpu/cpufreq/policy*/scaling_min_freq; do echo "3200000" > $file; done root@s15:/home/doug/temp# cat /sys/devices/system/cpu/cpufreq/policy*/scaling_min_freq 3200000 3200000 3200000 3200000 3200000 3200000 3200000 3200000 root@s15:/home/doug/temp# echo 42 > /sys/devices/system/cpu/intel_pstate/min_perf_pct root@s15:/home/doug/temp# cat /sys/devices/system/cpu/intel_pstate/min_perf_pct 42 ... (note 42% = 1600000 = processor minimum, and that is my expectation below.) root@s15:/home/doug/temp# cat /sys/devices/system/cpu/cpufreq/policy*/scaling_min_freq 3200000 3200000 3200000 3200000 3200000 3200000 3200000 3200000 I thought these minimum anomalies would cause problems for thermald, but for whatever reason, it seems to work properly. > --- > V3->V4: > - Reimplemented the solution using QoS constraints instead of > resolve_freq() callback. > > drivers/cpufreq/intel_pstate.c | 120 +++++++++++++++++++++++++++++++-- > 1 file changed, 116 insertions(+), 4 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index cc27d4c59dca..e9fbd6c36822 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -24,6 +24,7 @@ > #include <linux/fs.h> > #include <linux/acpi.h> > #include <linux/vmalloc.h> > +#include <linux/pm_qos.h> > #include <trace/events/power.h> > > #include <asm/div64.h> > @@ -1085,6 +1086,47 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b, > return count; > } > > +static struct cpufreq_driver intel_pstate; > + > +static void update_qos_request(enum dev_pm_qos_req_type type) > +{ > + int max_state, turbo_max, freq, i, perf_pct; > + struct dev_pm_qos_request *req; > + struct cpufreq_policy *policy; > + > + for_each_possible_cpu(i) { > + struct cpudata *cpu = all_cpu_data[i]; > + > + policy = cpufreq_cpu_get(i); > + if (!policy) > + continue; > + > + req = policy->driver_data; > + cpufreq_cpu_put(policy); > + > + if (!req) > + continue; > + > + if (hwp_active) > + intel_pstate_get_hwp_max(i, &turbo_max, &max_state); > + else > + turbo_max = cpu->pstate.turbo_pstate; > + > + if (type == DEV_PM_QOS_MIN_FREQUENCY) { Is it O.K. to assume if the passed op code is not DEV_PM_QOS_MIN_FREQUENCY then it must have been DEV_PM_QOS_MAX_FREQUENCY ? It is within this patch, but what about in future? > + perf_pct = global.min_perf_pct; > + } else { > + req++; > + perf_pct = global.max_perf_pct; > + } > + > + freq = DIV_ROUND_UP(turbo_max * perf_pct, 100); > + freq *= cpu->pstate.scaling; > + > + if (dev_pm_qos_update_request(req, freq)) > + pr_warn("Failed to update freq constraint: CPU%d\n", i); I get many of these messages (4520 so far, always in groups of 8 (I have 8 CPUs)), and have yet to figure out exactly why. It seems to actually be working fine. > + } > +} > + > static ssize_t store_max_perf_pct(struct kobject *a, struct kobj_attribute *b, > const char *buf, size_t count) > { > @@ -1108,7 +1150,10 @@ static ssize_t store_max_perf_pct(struct kobject *a, struct kobj_attribute *b, > > mutex_unlock(&intel_pstate_limits_lock); > > - intel_pstate_update_policies(); > + if (intel_pstate_driver == &intel_pstate) > + intel_pstate_update_policies(); > + else > + update_qos_request(DEV_PM_QOS_MAX_FREQUENCY); > > mutex_unlock(&intel_pstate_driver_lock); > > @@ -1139,7 +1184,10 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct kobj_attribute *b, > > mutex_unlock(&intel_pstate_limits_lock); > > - intel_pstate_update_policies(); > + if (intel_pstate_driver == &intel_pstate) > + intel_pstate_update_policies(); > + else > + update_qos_request(DEV_PM_QOS_MIN_FREQUENCY); > > mutex_unlock(&intel_pstate_driver_lock); > > @@ -2332,8 +2380,16 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy, > > static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy) > { > - int ret = __intel_pstate_cpu_init(policy); > + int max_state, turbo_max, min_freq, max_freq, ret; > + struct dev_pm_qos_request *req; > + struct cpudata *cpu; > + struct device *dev; > + > + dev = get_cpu_device(policy->cpu); > + if (!dev) > + return -ENODEV; > > + ret = __intel_pstate_cpu_init(policy); > if (ret) > return ret; > > @@ -2342,7 +2398,63 @@ static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy) > /* This reflects the intel_pstate_get_cpu_pstates() setting. */ > policy->cur = policy->cpuinfo.min_freq; > > + req = kcalloc(2, sizeof(*req), GFP_KERNEL); > + if (!req) { > + ret = -ENOMEM; > + goto pstate_exit; > + } > + > + cpu = all_cpu_data[policy->cpu]; > + > + if (hwp_active) > + intel_pstate_get_hwp_max(policy->cpu, &turbo_max, &max_state); > + else > + turbo_max = cpu->pstate.turbo_pstate; > + > + min_freq = DIV_ROUND_UP(turbo_max * global.min_perf_pct, 100); > + min_freq *= cpu->pstate.scaling; > + max_freq = DIV_ROUND_UP(turbo_max * global.max_perf_pct, 100); > + max_freq *= cpu->pstate.scaling; > + > + ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_MIN_FREQUENCY, > + min_freq); > + if (ret < 0) { > + dev_err(dev, "Failed to add min-freq constraint (%d)\n", ret); > + goto free_req; > + } > + > + ret = dev_pm_qos_add_request(dev, req + 1, DEV_PM_QOS_MAX_FREQUENCY, > + max_freq); > + if (ret < 0) { > + dev_err(dev, "Failed to add max-freq constraint (%d)\n", ret); > + goto remove_min_req; > + } > + > + policy->driver_data = req; > + > return 0; > + > +remove_min_req: > + dev_pm_qos_remove_request(req); > +free_req: > + kfree(req); > +pstate_exit: > + intel_pstate_exit_perf_limits(policy); > + > + return ret; > +} > + > +static int intel_cpufreq_cpu_exit(struct cpufreq_policy *policy) > +{ > + struct dev_pm_qos_request *req; > + > + req = policy->driver_data; > + > + dev_pm_qos_remove_request(req + 1); > + dev_pm_qos_remove_request(req); > + kfree(req); > + > + return intel_pstate_cpu_exit(policy); > } > > static struct cpufreq_driver intel_cpufreq = { > @@ -2351,7 +2463,7 @@ static struct cpufreq_driver intel_cpufreq = { > .target = intel_cpufreq_target, > .fast_switch = intel_cpufreq_fast_switch, > .init = intel_cpufreq_cpu_init, > - .exit = intel_pstate_cpu_exit, > + .exit = intel_cpufreq_cpu_exit, > .stop_cpu = intel_cpufreq_stop_cpu, > .update_limits = intel_pstate_update_limits, > .name = "intel_cpufreq", > -- > 2.21.0.rc0.269.g1a574e7a288b
, On Thu, Aug 8, 2019 at 6:25 PM Doug Smythies <dsmythies@telus.net> wrote: > > On 2019.08.07 00:06 Viresh Kumar wrote: > > Thanks for your work on this. > > > Intel pstate driver exposes min_perf_pct and max_perf_pct sysfs files, > > which can be used to force a limit on the min/max P state of the driver. > > Though these files eventually control the min/max frequencies that the > > CPUs will run at, they don't make a change to policy->min/max values. > > > > When the values of these files are changed (in passive mode of the > > driver), it leads to calling ->limits() callback of the cpufreq > > governors, like schedutil. On a call to it the governors shall > > forcefully update the frequency to come within the limits. Since the > > limits, i.e. policy->min/max, aren't updated by the driver, the > > governors fails to get the target freq within limit and sometimes aborts > > the update believing that the frequency is already set to the target > > value. > > > > This patch implements the QoS supported frequency constraints to update > > policy->min/max values whenever min_perf_pct or max_perf_pct files are > > updated. This is only done for the passive mode as of now, as the driver > > is already working fine in active mode. > > > > Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX") > > Reported-by: Doug Smythies <dsmythies@telus.net> > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > > Tested by: Doug Smythies <dsmythies@telus.net> > Thermald seems to now be working O.K. for all the governors. > > I do note that if one sets > /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq > It seems to override subsequent attempts via > /sys/devices/system/cpu/intel_pstate/max_perf_pct. > Myself, I find this confusing. > > So the question becomes which one is the "master"? For the min freq limit, the max of (scaling_min_freq, re-scaled min_perf_pct) should be used. For the max freq limit, the min of (scaling_max_freq, re-scaled max_perf_pct) should be used. Overall, the setting that "wins" is the one that causes the set of available frequencies to be narrower.
On 08-08-19, 09:25, Doug Smythies wrote: > On 2019.08.07 00:06 Viresh Kumar wrote: > Tested by: Doug Smythies <dsmythies@telus.net> > Thermald seems to now be working O.K. for all the governors. Thanks for testing Doug. > I do note that if one sets > /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq > It seems to override subsequent attempts via > /sys/devices/system/cpu/intel_pstate/max_perf_pct. > Myself, I find this confusing. > > So the question becomes which one is the "master"? No one is master, cpufreq takes all the requests for frequency constraints and tries to set the value based on aggregation of all. So for max frequency, the lowest value wins and is shown up in sysfs. So, everything looks okay to me. > > +static void update_qos_request(enum dev_pm_qos_req_type type) > > +{ > > + int max_state, turbo_max, freq, i, perf_pct; > > + struct dev_pm_qos_request *req; > > + struct cpufreq_policy *policy; > > + > > + for_each_possible_cpu(i) { > > + struct cpudata *cpu = all_cpu_data[i]; > > + > > + policy = cpufreq_cpu_get(i); > > + if (!policy) > > + continue; > > + > > + req = policy->driver_data; > > + cpufreq_cpu_put(policy); > > + > > + if (!req) > > + continue; > > + > > + if (hwp_active) > > + intel_pstate_get_hwp_max(i, &turbo_max, &max_state); > > + else > > + turbo_max = cpu->pstate.turbo_pstate; > > + > > + if (type == DEV_PM_QOS_MIN_FREQUENCY) { > > Is it O.K. to assume if the passed op code is > not DEV_PM_QOS_MIN_FREQUENCY > then it must have been > DEV_PM_QOS_MAX_FREQUENCY > ? > > It is within this patch, but what about in future? Yes, because it is called locally there is no need to add another if statement here. And reviews should catch it in future and I don't expect it to change much anyway. > > + perf_pct = global.min_perf_pct; > > + } else { > > + req++; > > + perf_pct = global.max_perf_pct; > > + } > > + > > + freq = DIV_ROUND_UP(turbo_max * perf_pct, 100); > > + freq *= cpu->pstate.scaling; > > + > > + if (dev_pm_qos_update_request(req, freq)) > > + pr_warn("Failed to update freq constraint: CPU%d\n", i); > > I get many of these messages (4520 so far, always in groups of 8 (I have 8 CPUs)), > and have yet to figure out exactly why. It seems to actually be working fine. Because of something I missed. dev_pm_qos_update_request() can return 1, when the constraint value gets changed. Will fix this patch. -- viresh
On 08-08-19, 23:35, Doug Smythies wrote: > O.K. While I understand the explanations, I still struggle with > this scenario: > > doug@s15:~/temp$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct > 50 <<< Note: 50% = 1.9 GHz in my system) > doug@s15:~/temp$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq:1900000 > /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq:1900000 > > At this point I am not certain what I'll get if I try to > set max_perf_pct to 100%, nor do I know how to find out > with a user command. > > So, I'll try it: > > doug@s15:~/temp$ echo 100 | sudo tee /sys/devices/system/cpu/intel_pstate/max_perf_pct > 100 > doug@s15:~/temp$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct > 100 <<< Note: 100% = 3.8 GHz in my system) > doug@s15:~/temp$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq:2200000 > /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq:2200000 > > I guess I had set it sometime earlier, forgot, and then didn't > get 3.8 Ghz as I had expected via max_perf_pct. Right, so the problem here (since ages) is that there is no file in sysfs to show the value earlier set by the user to scaling_max/min_freq. Rather when you try to read those files, cpufreq core gives you the current value of policy->min/max, which can come from so many factors, like userspace, thermal, max_perf_pct, etc. You saw 2200000 here because you must have set that value to scaling_max_freq earlier, else maybe thermal or other stuff constrained that value for you. Though the cpufreq core stores the value set by user and uses it to recalculate policy->max using it. To get rid of your constraint, set scaling_max_freq to the highest frequency and you will be good. -- viresh
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index cc27d4c59dca..e9fbd6c36822 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -24,6 +24,7 @@ #include <linux/fs.h> #include <linux/acpi.h> #include <linux/vmalloc.h> +#include <linux/pm_qos.h> #include <trace/events/power.h> #include <asm/div64.h> @@ -1085,6 +1086,47 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b, return count; } +static struct cpufreq_driver intel_pstate; + +static void update_qos_request(enum dev_pm_qos_req_type type) +{ + int max_state, turbo_max, freq, i, perf_pct; + struct dev_pm_qos_request *req; + struct cpufreq_policy *policy; + + for_each_possible_cpu(i) { + struct cpudata *cpu = all_cpu_data[i]; + + policy = cpufreq_cpu_get(i); + if (!policy) + continue; + + req = policy->driver_data; + cpufreq_cpu_put(policy); + + if (!req) + continue; + + if (hwp_active) + intel_pstate_get_hwp_max(i, &turbo_max, &max_state); + else + turbo_max = cpu->pstate.turbo_pstate; + + if (type == DEV_PM_QOS_MIN_FREQUENCY) { + perf_pct = global.min_perf_pct; + } else { + req++; + perf_pct = global.max_perf_pct; + } + + freq = DIV_ROUND_UP(turbo_max * perf_pct, 100); + freq *= cpu->pstate.scaling; + + if (dev_pm_qos_update_request(req, freq)) + pr_warn("Failed to update freq constraint: CPU%d\n", i); + } +} + static ssize_t store_max_perf_pct(struct kobject *a, struct kobj_attribute *b, const char *buf, size_t count) { @@ -1108,7 +1150,10 @@ static ssize_t store_max_perf_pct(struct kobject *a, struct kobj_attribute *b, mutex_unlock(&intel_pstate_limits_lock); - intel_pstate_update_policies(); + if (intel_pstate_driver == &intel_pstate) + intel_pstate_update_policies(); + else + update_qos_request(DEV_PM_QOS_MAX_FREQUENCY); mutex_unlock(&intel_pstate_driver_lock); @@ -1139,7 +1184,10 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct kobj_attribute *b, mutex_unlock(&intel_pstate_limits_lock); - intel_pstate_update_policies(); + if (intel_pstate_driver == &intel_pstate) + intel_pstate_update_policies(); + else + update_qos_request(DEV_PM_QOS_MIN_FREQUENCY); mutex_unlock(&intel_pstate_driver_lock); @@ -2332,8 +2380,16 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy, static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy) { - int ret = __intel_pstate_cpu_init(policy); + int max_state, turbo_max, min_freq, max_freq, ret; + struct dev_pm_qos_request *req; + struct cpudata *cpu; + struct device *dev; + + dev = get_cpu_device(policy->cpu); + if (!dev) + return -ENODEV; + ret = __intel_pstate_cpu_init(policy); if (ret) return ret; @@ -2342,7 +2398,63 @@ static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy) /* This reflects the intel_pstate_get_cpu_pstates() setting. */ policy->cur = policy->cpuinfo.min_freq; + req = kcalloc(2, sizeof(*req), GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto pstate_exit; + } + + cpu = all_cpu_data[policy->cpu]; + + if (hwp_active) + intel_pstate_get_hwp_max(policy->cpu, &turbo_max, &max_state); + else + turbo_max = cpu->pstate.turbo_pstate; + + min_freq = DIV_ROUND_UP(turbo_max * global.min_perf_pct, 100); + min_freq *= cpu->pstate.scaling; + max_freq = DIV_ROUND_UP(turbo_max * global.max_perf_pct, 100); + max_freq *= cpu->pstate.scaling; + + ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_MIN_FREQUENCY, + min_freq); + if (ret < 0) { + dev_err(dev, "Failed to add min-freq constraint (%d)\n", ret); + goto free_req; + } + + ret = dev_pm_qos_add_request(dev, req + 1, DEV_PM_QOS_MAX_FREQUENCY, + max_freq); + if (ret < 0) { + dev_err(dev, "Failed to add max-freq constraint (%d)\n", ret); + goto remove_min_req; + } + + policy->driver_data = req; + return 0; + +remove_min_req: + dev_pm_qos_remove_request(req); +free_req: + kfree(req); +pstate_exit: + intel_pstate_exit_perf_limits(policy); + + return ret; +} + +static int intel_cpufreq_cpu_exit(struct cpufreq_policy *policy) +{ + struct dev_pm_qos_request *req; + + req = policy->driver_data; + + dev_pm_qos_remove_request(req + 1); + dev_pm_qos_remove_request(req); + kfree(req); + + return intel_pstate_cpu_exit(policy); } static struct cpufreq_driver intel_cpufreq = { @@ -2351,7 +2463,7 @@ static struct cpufreq_driver intel_cpufreq = { .target = intel_cpufreq_target, .fast_switch = intel_cpufreq_fast_switch, .init = intel_cpufreq_cpu_init, - .exit = intel_pstate_cpu_exit, + .exit = intel_cpufreq_cpu_exit, .stop_cpu = intel_cpufreq_stop_cpu, .update_limits = intel_pstate_update_limits, .name = "intel_cpufreq",
Intel pstate driver exposes min_perf_pct and max_perf_pct sysfs files, which can be used to force a limit on the min/max P state of the driver. Though these files eventually control the min/max frequencies that the CPUs will run at, they don't make a change to policy->min/max values. When the values of these files are changed (in passive mode of the driver), it leads to calling ->limits() callback of the cpufreq governors, like schedutil. On a call to it the governors shall forcefully update the frequency to come within the limits. Since the limits, i.e. policy->min/max, aren't updated by the driver, the governors fails to get the target freq within limit and sometimes aborts the update believing that the frequency is already set to the target value. This patch implements the QoS supported frequency constraints to update policy->min/max values whenever min_perf_pct or max_perf_pct files are updated. This is only done for the passive mode as of now, as the driver is already working fine in active mode. Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX") Reported-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- V3->V4: - Reimplemented the solution using QoS constraints instead of resolve_freq() callback. drivers/cpufreq/intel_pstate.c | 120 +++++++++++++++++++++++++++++++-- 1 file changed, 116 insertions(+), 4 deletions(-) -- 2.21.0.rc0.269.g1a574e7a288b