6 files changed, 143 insertions, 2 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index 8b0c7db85a47..f8a8e46acb78 100644
--- a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -58,10 +58,12 @@ enum {
 };
 
 #define INTEL_MSR_RANGE         (0xffff)
+#define CPUID_6_ECX_APERFMPERF_CAPABILITY       (0x1)
 
 struct acpi_cpufreq_data {
         struct acpi_processor_performance *acpi_data;
         struct cpufreq_frequency_table *freq_table;
+        unsigned int max_freq;
         unsigned int resume;
         unsigned int cpu_feature;
 };
@@ -258,6 +260,100 @@ static u32 get_cur_val(cpumask_t mask)
         return cmd.val;
 }
 
+/*
+ * Return the measured active (C0) frequency on this CPU since last call
+ * to this function.
+ * Input: cpu number
+ * Return: Average CPU frequency in terms of max frequency (zero on error)
+ *
+ * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
+ * over a period of time, while CPU is in C0 state.
+ * IA32_MPERF counts at the rate of max advertised frequency
+ * IA32_APERF counts at the rate of actual CPU frequency
+ * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
+ * no meaning should be associated with absolute values of these MSRs.
+ */
+static unsigned int get_measured_perf(unsigned int cpu)
+{
+        union {
+                struct {
+                        u32 lo;
+                        u32 hi;
+                } split;
+                u64 whole;
+        } aperf_cur, mperf_cur;
+
+        cpumask_t saved_mask;
+        unsigned int perf_percent;
+        unsigned int retval;
+
+        saved_mask = current->cpus_allowed;
+        set_cpus_allowed(current, cpumask_of_cpu(cpu));
+        if (get_cpu() != cpu) {
+                /* We were not able to run on requested processor */
+                put_cpu();
+                return 0;
+        }
+
+        rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
+        rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
+
+        wrmsr(MSR_IA32_APERF, 0,0);
+        wrmsr(MSR_IA32_MPERF, 0,0);
+
+#ifdef __i386__
+        /*
+         * We dont want to do 64 bit divide with 32 bit kernel
+         * Get an approximate value. Return failure in case we cannot get
+         * an approximate value.
+         */
+        if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {
+                int shift_count;
+                u32 h;
+
+                h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);
+                shift_count = fls(h);
+
+                aperf_cur.whole >>= shift_count;
+                mperf_cur.whole >>= shift_count;
+        }
+
+        if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {
+                int shift_count = 7;
+                aperf_cur.split.lo >>= shift_count;
+                mperf_cur.split.lo >>= shift_count;
+        }
+
+        if (aperf_cur.split.lo && mperf_cur.split.lo) {
+                perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;
+        } else {
+                perf_percent = 0;
+        }
+
+#else
+        if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {
+                int shift_count = 7;
+                aperf_cur.whole >>= shift_count;
+                mperf_cur.whole >>= shift_count;
+        }
+
+        if (aperf_cur.whole && mperf_cur.whole) {
+                perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;
+        } else {
+                perf_percent = 0;
+        }
+
+#endif
+
+        retval = drv_data[cpu]->max_freq * perf_percent / 100;
+
+        put_cpu();
+        set_cpus_allowed(current, saved_mask);
+
+        dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);
+        return retval;
+}
+
 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
 {
         struct acpi_cpufreq_data *data = drv_data[cpu];
@@ -497,7 +593,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
         unsigned int valid_states = 0;
         unsigned int cpu = policy->cpu;
         struct acpi_cpufreq_data *data;
-        unsigned int l, h;
         unsigned int result = 0;
         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
         struct acpi_processor_performance *perf;
@@ -591,6 +686,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
         }
         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 
+        data->max_freq = perf->states[0].core_frequency * 1000;
         /* table init */
         for (i = 0; i < perf->state_count; i++) {
                 if (i > 0 && perf->states[i].core_frequency ==
@@ -625,6 +721,15 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
         /* notify BIOS that we exist */
         acpi_processor_notify_smm(THIS_MODULE);
 
+        /* Check for APERF/MPERF support in hardware */
+        if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
+                unsigned int ecx;
+                ecx = cpuid_ecx(6);
+                if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY) {
+                        acpi_cpufreq_driver.getavg = get_measured_perf;
+                }
+        }
+
         dprintk("CPU%u - ACPI performance management activated.\n", cpu);
         for (i = 0; i < perf->state_count; i++)
                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 86e69b7f9122..56c433e64d58 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1274,6 +1274,26 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 }
 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
 
+int cpufreq_driver_getavg(struct cpufreq_policy *policy)
+{
+        int ret = 0;
+
+        policy = cpufreq_cpu_get(policy->cpu);
+        if (!policy)
+                return -EINVAL;
+
+        mutex_lock(&policy->lock);
+
+        if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
+                ret = cpufreq_driver->getavg(policy->cpu);
+
+        mutex_unlock(&policy->lock);
+
+        cpufreq_cpu_put(policy);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpufreq_driver_getavg);
+
 /*
  * Locking: Must be called with the lock_cpu_hotplug() lock held
  * when "event" is CPUFREQ_GOV_LIMITS
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index bf8aa45d4f01..291cfe9400a1 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -393,8 +393,15 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
          * policy. To be safe, we focus 10 points under the threshold.
          */
         if (load < (dbs_tuners_ins.up_threshold - 10)) {
-                unsigned int freq_next = (policy->cur * load) /
+                unsigned int freq_next, freq_cur;
+
+                freq_cur = cpufreq_driver_getavg(policy);
+                if (!freq_cur)
+                        freq_cur = policy->cur;
+
+                freq_next = (freq_cur * load) /
                         (dbs_tuners_ins.up_threshold - 10);
+
                 if (!dbs_tuners_ins.powersave_bias) {
                         __cpufreq_driver_target(policy, freq_next,
                                         CPUFREQ_RELATION_L);
diff --git a/include/asm-i386/msr.h b/include/asm-i386/msr.h
index 62b76cd96957..0aa15fc8d918 100644
--- a/include/asm-i386/msr.h
+++ b/include/asm-i386/msr.h
@@ -125,6 +125,9 @@ static inline void wrmsrl (unsigned long msr, unsigned long long val)
 #define MSR_IA32_PERF_STATUS            0x198
 #define MSR_IA32_PERF_CTL               0x199
 
+#define MSR_IA32_MPERF                  0xE7
+#define MSR_IA32_APERF                  0xE8
+
 #define MSR_IA32_THERM_CONTROL          0x19a
 #define MSR_IA32_THERM_INTERRUPT        0x19b
 #define MSR_IA32_THERM_STATUS           0x19c
diff --git a/include/asm-x86_64/msr.h b/include/asm-x86_64/msr.h
index 37e194169fac..e61582288737 100644
--- a/include/asm-x86_64/msr.h
+++ b/include/asm-x86_64/msr.h
@@ -307,6 +307,9 @@ static inline unsigned int cpuid_edx(unsigned int op)
 #define MSR_IA32_PERF_STATUS            0x198
 #define MSR_IA32_PERF_CTL               0x199
 
+#define MSR_IA32_MPERF                  0xE7
+#define MSR_IA32_APERF                  0xE8
+
 #define MSR_IA32_THERM_CONTROL          0x19a
 #define MSR_IA32_THERM_INTERRUPT        0x19b
 #define MSR_IA32_THERM_STATUS           0x19c
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 4ea39fee99c7..7f008f6bfdc3 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -172,6 +172,8 @@ extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
                                    unsigned int relation);
 
 
+extern int cpufreq_driver_getavg(struct cpufreq_policy *policy);
+
 int cpufreq_register_governor(struct cpufreq_governor *governor);
 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 
@@ -204,6 +206,7 @@ struct cpufreq_driver {
         unsigned int    (*get)  (unsigned int cpu);
 
         /* optional */
+        unsigned int (*getavg)  (unsigned int cpu);
         int     (*exit)         (struct cpufreq_policy *policy);
         int     (*suspend)      (struct cpufreq_policy *policy, pm_message_t pmsg);
         int     (*resume)       (struct cpufreq_policy *policy);