cpufreq: powernv: Add sysfs attributes to show throttle stats

Create sysfs attributes to export throttle information in
/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory. The
newly added sysfs files are as follows:

 1)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
 2)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub-turbo_stat
 3)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
 4)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
 5)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
 6)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
 7)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
 8)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset

Detailed explanation of each attribute is added to
Documentation/ABI/testing/sysfs-devices-system-cpu

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index b683e8e..1650133 100644 (file)
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -271,3 +271,72 @@ Description:       Parameters for the CPU cache attributes
                        - WriteBack: data is written only to the cache line and
                                     the modified cache line is written to main
                                     memory only when it is replaced
+
+What:          /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
+               /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
+Date:          March 2016
+Contact:       Linux kernel mailing list <linux-kernel@vger.kernel.org>
+               Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   POWERNV CPUFreq driver's frequency throttle stats directory and
+               attributes
+
+               'cpuX/cpufreq/throttle_stats' directory contains the CPU frequency
+               throttle stat attributes for the chip. The throttle stats of a cpu
+               is common across all the cpus belonging to a chip. Below are the
+               throttle attributes exported in the 'throttle_stats' directory:
+
+               - turbo_stat : This file gives the total number of times the max
+               frequency is throttled to lower frequency in turbo (at and above
+               nominal frequency) range of frequencies.
+
+               - sub_turbo_stat : This file gives the total number of times the
+               max frequency is throttled to lower frequency in sub-turbo(below
+               nominal frequency) range of frequencies.
+
+               - unthrottle : This file gives the total number of times the max
+               frequency is unthrottled after being throttled.
+
+               - powercap : This file gives the total number of times the max
+               frequency is throttled due to 'Power Capping'.
+
+               - overtemp : This file gives the total number of times the max
+               frequency is throttled due to 'CPU Over Temperature'.
+
+               - supply_fault : This file gives the total number of times the
+               max frequency is throttled due to 'Power Supply Failure'.
+
+               - overcurrent : This file gives the total number of times the
+               max frequency is throttled due to 'Overcurrent'.
+
+               - occ_reset : This file gives the total number of times the max
+               frequency is throttled due to 'OCC Reset'.
+
+               The sysfs attributes representing different throttle reasons like
+               powercap, overtemp, supply_fault, overcurrent and occ_reset map to
+               the reasons provided by OCC firmware for throttling the frequency.
+
+What:          /sys/devices/system/cpu/cpufreq/policyX/throttle_stats
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent
+               /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
+Date:          March 2016
+Contact:       Linux kernel mailing list <linux-kernel@vger.kernel.org>
+               Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   POWERNV CPUFreq driver's frequency throttle stats directory and
+               attributes
+
+               'policyX/throttle_stats' directory and all the attributes are same as
+               the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
+               attributes which give the frequency throttle information of the chip.

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index a00bcc2..39ac78c 100644 (file)
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -54,6 +54,16 @@ static const char * const throttle_reason[] = {
        "OCC Reset"
 };
 
+enum throttle_reason_type {
+       NO_THROTTLE = 0,
+       POWERCAP,
+       CPU_OVERTEMP,
+       POWER_SUPPLY_FAILURE,
+       OVERCURRENT,
+       OCC_RESET_THROTTLE,
+       OCC_MAX_REASON
+};
+
 static struct chip {
        unsigned int id;
        bool throttled;
@@ -61,6 +71,9 @@ static struct chip {
        u8 throttle_reason;
        cpumask_t mask;
        struct work_struct throttle;
+       int throttle_turbo;
+       int throttle_sub_turbo;
+       int reason[OCC_MAX_REASON];
 } *chips;
 
 static int nr_chips;
@@ -196,6 +209,42 @@ static struct freq_attr *powernv_cpu_freq_attr[] = {
        NULL,
 };
 
+#define throttle_attr(name, member)                                    \
+static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)   \
+{                                                                      \
+       struct chip *chip = per_cpu(chip_info, policy->cpu);            \
+                                                                       \
+       return sprintf(buf, "%u\n", chip->member);                      \
+}                                                                      \
+                                                                       \
+static struct freq_attr throttle_attr_##name = __ATTR_RO(name)         \
+
+throttle_attr(unthrottle, reason[NO_THROTTLE]);
+throttle_attr(powercap, reason[POWERCAP]);
+throttle_attr(overtemp, reason[CPU_OVERTEMP]);
+throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
+throttle_attr(overcurrent, reason[OVERCURRENT]);
+throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
+throttle_attr(turbo_stat, throttle_turbo);
+throttle_attr(sub_turbo_stat, throttle_sub_turbo);
+
+static struct attribute *throttle_attrs[] = {
+       &throttle_attr_unthrottle.attr,
+       &throttle_attr_powercap.attr,
+       &throttle_attr_overtemp.attr,
+       &throttle_attr_supply_fault.attr,
+       &throttle_attr_overcurrent.attr,
+       &throttle_attr_occ_reset.attr,
+       &throttle_attr_turbo_stat.attr,
+       &throttle_attr_sub_turbo_stat.attr,
+       NULL,
+};
+
+static const struct attribute_group throttle_attr_grp = {
+       .name   = "throttle_stats",
+       .attrs  = throttle_attrs,
+};
+
 /* Helper routines */
 
 /* Access helpers to power mgt SPR */
@@ -338,10 +387,14 @@ static void powernv_cpufreq_throttle_check(void *data)
                if (chip->throttled)
                        goto next;
                chip->throttled = true;
-               if (pmsr_pmax < powernv_pstate_info.nominal)
+               if (pmsr_pmax < powernv_pstate_info.nominal) {
                        pr_warn_once("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",
                                     cpu, chip->id, pmsr_pmax,
                                     powernv_pstate_info.nominal);
+                       chip->throttle_sub_turbo++;
+               } else {
+                       chip->throttle_turbo++;
+               }
                trace_powernv_throttle(chip->id,
                                      throttle_reason[chip->throttle_reason],
                                      pmsr_pmax);
@@ -408,6 +461,21 @@ 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);
 
+       if (!policy->driver_data) {
+               int ret;
+
+               ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
+               if (ret) {
+                       pr_info("Failed to create throttle stats directory for cpu %d\n",
+                               policy->cpu);
+                       return ret;
+               }
+               /*
+                * policy->driver_data is used as a flag for one-time
+                * creation of throttle sysfs files.
+                */
+               policy->driver_data = policy;
+       }
        return cpufreq_table_validate_and_show(policy, powernv_freqs);
 }
 
@@ -514,8 +582,10 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
                                break;
 
                if (omsg.throttle_status >= 0 &&
-                   omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS)
+                   omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
                        chips[i].throttle_reason = omsg.throttle_status;
+                       chips[i].reason[omsg.throttle_status]++;
+               }
 
                if (!omsg.throttle_status)
                        chips[i].restore = true;