From: Guenter Roeck on
On Wed, 2010-07-28 at 15:00 -0400, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu(a)intel.com>
>
> Power limit notification feature is published in Intel 64 and IA-32
> Architectures SDMV Vol 3A 14.5.6 Power Limit Notification.
>
> It is implemented first on Intel Sandy Bridge platform.
>
> The patch handles notification interrupt. Interrupt handler dumps power limit
> information in log_buf, logs the event in mce log, and increases the event
> counters (core_power_limit and package_power_limit). Upper level applications
> could use the data to detect system health or diagnose functionality/performance
> issues.
>
> In the future, the event could be handled in a more fancy way.
>
> Signed-off-by: Fenghua Yu <fenghua.yu(a)intel.com>
> Reviewed-by: Len Brown <len.brown(a)intel.com>
> ---
> arch/x86/include/asm/msr-index.h | 4 +
> arch/x86/kernel/cpu/mcheck/therm_throt.c | 186 +++++++++++++++++++++---------
> 2 files changed, 136 insertions(+), 54 deletions(-)
>
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
> index f1c1b82..f3c8a7a 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -226,10 +226,12 @@
>
> #define THERM_INT_HIGH_ENABLE (1 << 0)
> #define THERM_INT_LOW_ENABLE (1 << 1)
> +#define THERM_INT_PLN_ENABLE (1 << 24)
>
> #define MSR_IA32_THERM_STATUS 0x0000019c
>
> #define THERM_STATUS_PROCHOT (1 << 0)
> +#define THERM_STATUS_POWER_LIMIT (1 << 10)
>
> #define MSR_THERM2_CTL 0x0000019d
>
> @@ -242,11 +244,13 @@
> #define MSR_IA32_PACKAGE_THERM_STATUS 0x000001b1
>
> #define PACKAGE_THERM_STATUS_PROCHOT (1 << 0)
> +#define PACKAGE_THERM_STATUS_POWER_LIMIT (1 << 10)
>
> #define MSR_IA32_PACKAGE_THERM_INTERRUPT 0x000001b2
>
> #define PACKAGE_THERM_INT_HIGH_ENABLE (1 << 0)
> #define PACKAGE_THERM_INT_LOW_ENABLE (1 << 1)
> +#define PACKAGE_THERM_INT_PLN_ENABLE (1 << 24)
>
> /* MISC_ENABLE bits: architectural */
> #define MSR_IA32_MISC_ENABLE_FAST_STRING (1ULL << 0)
> diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
> index d307f9f..0c3d1e0 100644
> --- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
> +++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
> @@ -34,20 +34,25 @@
> /* How long to wait between reporting thermal events */
> #define CHECK_INTERVAL (300 * HZ)
>
> +#define THERMAL_THROTTLING_EVENT 0
> +#define POWER_LIMIT_EVENT 1
> +
> /*
> - * Current thermal throttling state:
> + * Current thermal event state:
> */
> struct _thermal_state {
> - bool is_throttled;
> -
> + bool new_event;
> + int event;
> u64 next_check;
> - unsigned long throttle_count;
> - unsigned long last_throttle_count;
> + unsigned long count;
> + unsigned long last_count;
> };
>
> struct thermal_state {
> - struct _thermal_state core;
> - struct _thermal_state package;
> + struct _thermal_state core_throttle;
> + struct _thermal_state core_power_limit;
> + struct _thermal_state package_throttle;
> + struct _thermal_state package_power_limit;
> };
>
> static DEFINE_PER_CPU(struct thermal_state, thermal_state);
> @@ -62,9 +67,9 @@ static u32 lvtthmr_init __read_mostly;
> therm_throt_sysdev_show_##_name, \
> NULL) \
>
> -#define define_therm_throt_sysdev_show_func(level, name) \
> +#define define_therm_throt_sysdev_show_func(event, name) \
> \
> -static ssize_t therm_throt_sysdev_show_##level##_##name( \
> +static ssize_t therm_throt_sysdev_show_##event##_##name( \
> struct sys_device *dev, \
> struct sysdev_attribute *attr, \
> char *buf) \
> @@ -75,7 +80,7 @@ static ssize_t therm_throt_sysdev_show_##level##_##name( \
> preempt_disable(); /* CPU hotplug */ \
> if (cpu_online(cpu)) { \
> ret = sprintf(buf, "%lu\n", \
> - per_cpu(thermal_state, cpu).level.name); \
> + per_cpu(thermal_state, cpu).event.name); \
> } else \
> ret = 0; \
> preempt_enable(); \
> @@ -83,23 +88,32 @@ static ssize_t therm_throt_sysdev_show_##level##_##name( \
> return ret; \
> }
>
> -define_therm_throt_sysdev_show_func(core, throttle_count);
> +define_therm_throt_sysdev_show_func(core_throttle, count);
> define_therm_throt_sysdev_one_ro(core_throttle_count);
>
> -define_therm_throt_sysdev_show_func(package, throttle_count);
> +define_therm_throt_sysdev_show_func(core_power_limit, count);
> +define_therm_throt_sysdev_one_ro(core_power_limit_count);
> +
> +define_therm_throt_sysdev_show_func(package_throttle, count);
> define_therm_throt_sysdev_one_ro(package_throttle_count);
>
> +define_therm_throt_sysdev_show_func(package_power_limit, count);
> +define_therm_throt_sysdev_one_ro(package_power_limit_count);
> +
> static struct attribute *thermal_throttle_attrs[] = {
> &attr_core_throttle_count.attr,
> NULL
> };
>
> -static struct attribute_group thermal_throttle_attr_group = {
> +static struct attribute_group thermal_attr_group = {
> .attrs = thermal_throttle_attrs,
> .name = "thermal_throttle"
> };
> #endif /* CONFIG_SYSFS */
>
> +#define CORE_LEVEL 0
> +#define PACKAGE_LEVEL 1
> +
> /***
> * therm_throt_process - Process thermal throttling event from interrupt
> * @curr: Whether the condition is current or not (boolean), since the
> @@ -116,49 +130,73 @@ static struct attribute_group thermal_throttle_attr_group = {
> * 1 : Event should be logged further, and a message has been
> * printed to the syslog.
> */
> -#define CORE_LEVEL 0
> -#define PACKAGE_LEVEL 1
> -static int therm_throt_process(bool is_throttled, int level)
> +static int therm_throt_process(bool new_event, int event, int level)
> {
> struct _thermal_state *state;
> - unsigned int this_cpu;
> - bool was_throttled;
> + unsigned int this_cpu = smp_processor_id();
> + bool old_event;
> u64 now;
> + struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
> +
> + if (!new_event)
> + return 0;
>
As a result of this check and return, events will never be reset.

> - this_cpu = smp_processor_id();
> now = get_jiffies_64();
> - if (level == CORE_LEVEL)
> - state = &per_cpu(thermal_state, this_cpu).core;
> - else
> - state = &per_cpu(thermal_state, this_cpu).package;
> + if (level == CORE_LEVEL) {
> + if (event == THERMAL_THROTTLING_EVENT)
> + state = &pstate->core_throttle;
> + else if (event == POWER_LIMIT_EVENT)
> + state = &pstate->core_power_limit;
> + else
> + return 0;
> + } else if (level == PACKAGE_LEVEL) {
> + if (event == THERMAL_THROTTLING_EVENT)
> + state = &pstate->package_throttle;
> + else if (event == POWER_LIMIT_EVENT)
> + state = &pstate->package_power_limit;
> + else
> + return 0;
> + } else
> + return 0;
>
> - was_throttled = state->is_throttled;
> - state->is_throttled = is_throttled;
> + old_event = state->new_event;
> + state->new_event = new_event;
>
> - if (is_throttled)
> - state->throttle_count++;
> + if (new_event)
> + state->count++;
>
> if (time_before64(now, state->next_check) &&
> - state->throttle_count != state->last_throttle_count)
> + state->count != state->last_count)
> return 0;
>
> state->next_check = now + CHECK_INTERVAL;
> - state->last_throttle_count = state->throttle_count;
> + state->last_count = state->count;
>
> /* if we just entered the thermal event */
> - if (is_throttled) {
> - printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
> - this_cpu,
> - level == CORE_LEVEL ? "Core" : "Package",
> - state->throttle_count);
> + if (new_event) {
> + if (event == THERMAL_THROTTLING_EVENT)
> + printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
> + this_cpu,
> + level == CORE_LEVEL ? "Core" : "Package",
> + state->count);
> + else
> + printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
> + this_cpu,
> + level == CORE_LEVEL ? "Core" : "Package",
> + state->count);
>
> add_taint(TAINT_MACHINE_CHECK);
> return 1;
> }

Since new_event is always true, code below will never be executed.
That doesn't make sense to me.

> - if (was_throttled) {
> - printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
> - this_cpu,
> - level == CORE_LEVEL ? "Core" : "Package");
> + if (old_event) {
> + if (event == THERMAL_THROTTLING_EVENT)
> + printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
> + this_cpu,
> + level == CORE_LEVEL ? "Core" : "Package");
> + else
> + printk(KERN_INFO "CPU%d: %s power limit normal\n",
> + this_cpu,
> + level == CORE_LEVEL ? "Core" : "Package");
> return 1;
> }
>
> @@ -172,21 +210,29 @@ static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
> int err;
> struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
>
> - err = sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group);
> + err = sysfs_create_group(&sys_dev->kobj, &thermal_attr_group);
> if (err)
> return err;
>
> + if (cpu_has(c, X86_FEATURE_PLN))
> + err = sysfs_add_file_to_group(&sys_dev->kobj,
> + &attr_core_power_limit_count.attr,
> + thermal_attr_group.name);
> if (cpu_has(c, X86_FEATURE_PTS))
> err = sysfs_add_file_to_group(&sys_dev->kobj,
> &attr_package_throttle_count.attr,
> - thermal_throttle_attr_group.name);
> + thermal_attr_group.name);
> + if (cpu_has(c, X86_FEATURE_PLN))
> + err = sysfs_add_file_to_group(&sys_dev->kobj,
> + &attr_package_power_limit_count.attr,
> + thermal_attr_group.name);
>
> return err;
> }
>
> static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
> {
> - sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
> + sysfs_remove_group(&sys_dev->kobj, &thermal_attr_group);
> }
>
> /* Mutex protecting device creation against CPU hotplug: */
> @@ -257,6 +303,17 @@ device_initcall(thermal_throttle_init_device);
>
> #endif /* CONFIG_SYSFS */
>
> +/*
> + * Set up the most two significant bit to notify mce log that this thermal
> + * event type.
> + * This is a temp solution. May be changed in the future with mce log
> + * infrasture.
> + */
> +#define CORE_THROTTLED (0)
> +#define CORE_POWER_LIMIT ((__u64)1 << 62)
> +#define PACKAGE_THROTTLED ((__u64)2 << 62)
> +#define PACKAGE_POWER_LIMIT ((__u64)3 << 62)
> +
> /* Thermal transition interrupt handler */
> static void intel_thermal_interrupt(void)
> {
> @@ -264,21 +321,31 @@ static void intel_thermal_interrupt(void)
> struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
>
> rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
> +
> if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
> + THERMAL_THROTTLING_EVENT,
> CORE_LEVEL) != 0)
> - mce_log_therm_throt_event(msr_val);
> + mce_log_therm_throt_event(CORE_THROTTLED | msr_val);
> +
> + if (cpu_has(c, X86_FEATURE_PLN))
> + if (therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
> + POWER_LIMIT_EVENT,
> + CORE_LEVEL) != 0)
> + mce_log_therm_throt_event(CORE_POWER_LIMIT | msr_val);
>
> if (cpu_has(c, X86_FEATURE_PTS)) {
> rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
> if (therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
> + THERMAL_THROTTLING_EVENT,
> PACKAGE_LEVEL) != 0)
> - /*
> - * Set up the most significant bit to notify mce log
> - * that this thermal event is a package level event.
> - * This is a temp solution. May be changed in the future
> - * with mce log infrasture.
> - */
> - mce_log_therm_throt_event(((__u64)1 << 63) | msr_val);
> + mce_log_therm_throt_event(PACKAGE_THROTTLED | msr_val);
> + if (cpu_has(c, X86_FEATURE_PLN))
> + if (therm_throt_process(msr_val &
> + PACKAGE_THERM_STATUS_POWER_LIMIT,
> + POWER_LIMIT_EVENT,
> + PACKAGE_LEVEL) != 0)
> + mce_log_therm_throt_event(PACKAGE_POWER_LIMIT
> + | msr_val);
> }
> }
>
> @@ -381,14 +448,25 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
> apic_write(APIC_LVTTHMR, h);
>
> rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
> - wrmsr(MSR_IA32_THERM_INTERRUPT,
> - l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
> + if (cpu_has(c, X86_FEATURE_PLN))
> + wrmsr(MSR_IA32_THERM_INTERRUPT,
> + l | (THERM_INT_LOW_ENABLE
> + | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
> + else
> + wrmsr(MSR_IA32_THERM_INTERRUPT,
> + l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
>
> if (cpu_has(c, X86_FEATURE_PTS)) {
> rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
> - wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
> - l | (PACKAGE_THERM_INT_LOW_ENABLE
> - | PACKAGE_THERM_INT_HIGH_ENABLE), h);
> + if (cpu_has(c, X86_FEATURE_PLN))
> + wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
> + l | (PACKAGE_THERM_INT_LOW_ENABLE
> + | PACKAGE_THERM_INT_HIGH_ENABLE
> + | PACKAGE_THERM_INT_PLN_ENABLE), h);
> + else
> + wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
> + l | (PACKAGE_THERM_INT_LOW_ENABLE
> + | PACKAGE_THERM_INT_HIGH_ENABLE), h);
> }
>
> smp_thermal_vector = intel_thermal_interrupt;
> --
> 1.7.2
>


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