perf_counters: account NMI interrupts
[deliverable/linux.git] / arch / x86 / kernel / cpu / perf_counter.c
index 43c8e9a38b4e2d702b81a5797a3a2396cce3d406..9901e46998d1a59d006eff17111046e0e539ca52 100644 (file)
@@ -16,7 +16,7 @@
 #include <linux/kdebug.h>
 #include <linux/sched.h>
 
-#include <asm/intel_arch_perfmon.h>
+#include <asm/perf_counter.h>
 #include <asm/apic.h>
 
 static bool perf_counters_initialized __read_mostly;
@@ -24,16 +24,17 @@ static bool perf_counters_initialized __read_mostly;
 /*
  * Number of (generic) HW counters:
  */
-static int nr_hw_counters __read_mostly;
-static u32 perf_counter_mask __read_mostly;
+static int nr_counters_generic __read_mostly;
+static u64 perf_counter_mask __read_mostly;
+static u64 counter_value_mask __read_mostly;
 
-/* No support for fixed function counters yet */
-
-#define MAX_HW_COUNTERS                8
+static int nr_counters_fixed __read_mostly;
 
 struct cpu_hw_counters {
-       struct perf_counter     *counters[MAX_HW_COUNTERS];
-       unsigned long           used[BITS_TO_LONGS(MAX_HW_COUNTERS)];
+       struct perf_counter     *counters[X86_PMC_IDX_MAX];
+       unsigned long           used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
+       unsigned long           interrupts;
+       u64                     global_enable;
 };
 
 /*
@@ -41,17 +42,58 @@ struct cpu_hw_counters {
  */
 static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters);
 
-const int intel_perfmon_event_map[] =
+static const int intel_perfmon_event_map[] =
 {
-  [PERF_COUNT_CYCLES]                  = 0x003c,
+  [PERF_COUNT_CPU_CYCLES]              = 0x003c,
   [PERF_COUNT_INSTRUCTIONS]            = 0x00c0,
   [PERF_COUNT_CACHE_REFERENCES]                = 0x4f2e,
   [PERF_COUNT_CACHE_MISSES]            = 0x412e,
   [PERF_COUNT_BRANCH_INSTRUCTIONS]     = 0x00c4,
   [PERF_COUNT_BRANCH_MISSES]           = 0x00c5,
+  [PERF_COUNT_BUS_CYCLES]              = 0x013c,
 };
 
-const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map);
+static const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map);
+
+/*
+ * Propagate counter elapsed time into the generic counter.
+ * Can only be executed on the CPU where the counter is active.
+ * Returns the delta events processed.
+ */
+static void
+x86_perf_counter_update(struct perf_counter *counter,
+                       struct hw_perf_counter *hwc, int idx)
+{
+       u64 prev_raw_count, new_raw_count, delta;
+
+       /*
+        * Careful: an NMI might modify the previous counter value.
+        *
+        * Our tactic to handle this is to first atomically read and
+        * exchange a new raw count - then add that new-prev delta
+        * count to the generic counter atomically:
+        */
+again:
+       prev_raw_count = atomic64_read(&hwc->prev_count);
+       rdmsrl(hwc->counter_base + idx, new_raw_count);
+
+       if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
+                                       new_raw_count) != prev_raw_count)
+               goto again;
+
+       /*
+        * Now we have the new raw value and have updated the prev
+        * timestamp already. We can now calculate the elapsed delta
+        * (counter-)time and add that to the generic counter.
+        *
+        * Careful, not all hw sign-extends above the physical width
+        * of the count, so we do that by clipping the delta to 32 bits:
+        */
+       delta = (u64)(u32)((s32)new_raw_count - (s32)prev_raw_count);
+
+       atomic64_add(delta, &counter->count);
+       atomic64_sub(delta, &hwc->period_left);
+}
 
 /*
  * Setup the hardware configuration for a given hw_event_type
@@ -81,19 +123,16 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
                        hwc->nmi = 1;
        }
 
-       hwc->config_base        = MSR_ARCH_PERFMON_EVENTSEL0;
-       hwc->counter_base       = MSR_ARCH_PERFMON_PERFCTR0;
-
        hwc->irq_period         = hw_event->irq_period;
        /*
         * Intel PMCs cannot be accessed sanely above 32 bit width,
         * so we install an artificial 1<<31 period regardless of
         * the generic counter period:
         */
-       if (!hwc->irq_period)
+       if ((s64)hwc->irq_period <= 0 || hwc->irq_period > 0x7FFFFFFF)
                hwc->irq_period = 0x7FFFFFFF;
 
-       hwc->next_count = -(s32)hwc->irq_period;
+       atomic64_set(&hwc->period_left, hwc->irq_period);
 
        /*
         * Raw event type provide the config in the event structure
@@ -113,175 +152,275 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
        return 0;
 }
 
-void hw_perf_enable_all(void)
+u64 hw_perf_save_disable(void)
 {
-       wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0);
+       u64 ctrl;
+
+       if (unlikely(!perf_counters_initialized))
+               return 0;
+
+       rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
+       wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+
+       return ctrl;
 }
+EXPORT_SYMBOL_GPL(hw_perf_save_disable);
 
-void hw_perf_restore_ctrl(u64 ctrl)
+void hw_perf_restore(u64 ctrl)
 {
-       wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0);
+       if (unlikely(!perf_counters_initialized))
+               return;
+
+       wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
 }
-EXPORT_SYMBOL_GPL(hw_perf_restore_ctrl);
+EXPORT_SYMBOL_GPL(hw_perf_restore);
 
-u64 hw_perf_disable_all(void)
+static inline void
+__pmc_fixed_disable(struct perf_counter *counter,
+                   struct hw_perf_counter *hwc, unsigned int __idx)
 {
-       u64 ctrl;
+       int idx = __idx - X86_PMC_IDX_FIXED;
+       u64 ctrl_val, mask;
+       int err;
 
-       rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
-       wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0);
-       return ctrl;
+       mask = 0xfULL << (idx * 4);
+
+       rdmsrl(hwc->config_base, ctrl_val);
+       ctrl_val &= ~mask;
+       err = checking_wrmsrl(hwc->config_base, ctrl_val);
 }
-EXPORT_SYMBOL_GPL(hw_perf_disable_all);
 
 static inline void
-__x86_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx)
+__pmc_generic_disable(struct perf_counter *counter,
+                          struct hw_perf_counter *hwc, unsigned int idx)
 {
-       wrmsr(hwc->config_base + idx, hwc->config, 0);
+       if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL))
+               __pmc_fixed_disable(counter, hwc, idx);
+       else
+               wrmsr_safe(hwc->config_base + idx, hwc->config, 0);
 }
 
-static DEFINE_PER_CPU(u64, prev_next_count[MAX_HW_COUNTERS]);
+static DEFINE_PER_CPU(u64, prev_left[X86_PMC_IDX_MAX]);
 
-static void __hw_perf_counter_set_period(struct hw_perf_counter *hwc, int idx)
+/*
+ * Set the next IRQ period, based on the hwc->period_left value.
+ * To be called with the counter disabled in hw:
+ */
+static void
+__hw_perf_counter_set_period(struct perf_counter *counter,
+                            struct hw_perf_counter *hwc, int idx)
 {
-       per_cpu(prev_next_count[idx], smp_processor_id()) = hwc->next_count;
+       s64 left = atomic64_read(&hwc->period_left);
+       s32 period = hwc->irq_period;
+       int err;
+
+       /*
+        * If we are way outside a reasoable range then just skip forward:
+        */
+       if (unlikely(left <= -period)) {
+               left = period;
+               atomic64_set(&hwc->period_left, left);
+       }
 
-       wrmsr(hwc->counter_base + idx, hwc->next_count, 0);
+       if (unlikely(left <= 0)) {
+               left += period;
+               atomic64_set(&hwc->period_left, left);
+       }
+
+       per_cpu(prev_left[idx], smp_processor_id()) = left;
+
+       /*
+        * The hw counter starts counting from this counter offset,
+        * mark it to be able to extra future deltas:
+        */
+       atomic64_set(&hwc->prev_count, (u64)-left);
+
+       err = checking_wrmsrl(hwc->counter_base + idx,
+                            (u64)(-left) & counter_value_mask);
 }
 
-static void __x86_perf_counter_enable(struct hw_perf_counter *hwc, int idx)
+static inline void
+__pmc_fixed_enable(struct perf_counter *counter,
+                  struct hw_perf_counter *hwc, unsigned int __idx)
 {
-       wrmsr(hwc->config_base + idx,
-             hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
+       int idx = __idx - X86_PMC_IDX_FIXED;
+       u64 ctrl_val, bits, mask;
+       int err;
+
+       /*
+        * Enable IRQ generation (0x8) and ring-3 counting (0x2),
+        * and enable ring-0 counting if allowed:
+        */
+       bits = 0x8ULL | 0x2ULL;
+       if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
+               bits |= 0x1;
+       bits <<= (idx * 4);
+       mask = 0xfULL << (idx * 4);
+
+       rdmsrl(hwc->config_base, ctrl_val);
+       ctrl_val &= ~mask;
+       ctrl_val |= bits;
+       err = checking_wrmsrl(hwc->config_base, ctrl_val);
 }
 
-static void x86_perf_counter_enable(struct perf_counter *counter)
+static void
+__pmc_generic_enable(struct perf_counter *counter,
+                         struct hw_perf_counter *hwc, int idx)
 {
-       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
-       struct hw_perf_counter *hwc = &counter->hw;
-       int idx = hwc->idx;
+       if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL))
+               __pmc_fixed_enable(counter, hwc, idx);
+       else
+               wrmsr(hwc->config_base + idx,
+                     hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
+}
 
-       /* Try to get the previous counter again */
-       if (test_and_set_bit(idx, cpuc->used)) {
-               idx = find_first_zero_bit(cpuc->used, nr_hw_counters);
-               set_bit(idx, cpuc->used);
-               hwc->idx = idx;
-       }
+static int
+fixed_mode_idx(struct perf_counter *counter, struct hw_perf_counter *hwc)
+{
+       unsigned int event;
 
-       perf_counters_lapic_init(hwc->nmi);
+       if (unlikely(hwc->nmi))
+               return -1;
 
-       __x86_perf_counter_disable(hwc, idx);
+       event = hwc->config & ARCH_PERFMON_EVENT_MASK;
 
-       cpuc->counters[idx] = counter;
+       if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_INSTRUCTIONS]))
+               return X86_PMC_IDX_FIXED_INSTRUCTIONS;
+       if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_CPU_CYCLES]))
+               return X86_PMC_IDX_FIXED_CPU_CYCLES;
+       if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_BUS_CYCLES]))
+               return X86_PMC_IDX_FIXED_BUS_CYCLES;
 
-       __hw_perf_counter_set_period(hwc, idx);
-       __x86_perf_counter_enable(hwc, idx);
+       return -1;
 }
 
-static void __hw_perf_save_counter(struct perf_counter *counter,
-                                  struct hw_perf_counter *hwc, int idx)
+/*
+ * Find a PMC slot for the freshly enabled / scheduled in counter:
+ */
+static int pmc_generic_enable(struct perf_counter *counter)
 {
-       s64 raw = -1;
-       s64 delta;
+       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+       struct hw_perf_counter *hwc = &counter->hw;
+       int idx;
 
-       /*
-        * Get the raw hw counter value:
-        */
-       rdmsrl(hwc->counter_base + idx, raw);
+       idx = fixed_mode_idx(counter, hwc);
+       if (idx >= 0) {
+               /*
+                * Try to get the fixed counter, if that is already taken
+                * then try to get a generic counter:
+                */
+               if (test_and_set_bit(idx, cpuc->used))
+                       goto try_generic;
 
-       /*
-        * Rebase it to zero (it started counting at -irq_period),
-        * to see the delta since ->prev_count:
-        */
-       delta = (s64)hwc->irq_period + (s64)(s32)raw;
+               hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
+               /*
+                * We set it so that counter_base + idx in wrmsr/rdmsr maps to
+                * MSR_ARCH_PERFMON_FIXED_CTR0 ... CTR2:
+                */
+               hwc->counter_base =
+                       MSR_ARCH_PERFMON_FIXED_CTR0 - X86_PMC_IDX_FIXED;
+               hwc->idx = idx;
+       } else {
+               idx = hwc->idx;
+               /* Try to get the previous generic counter again */
+               if (test_and_set_bit(idx, cpuc->used)) {
+try_generic:
+                       idx = find_first_zero_bit(cpuc->used, nr_counters_generic);
+                       if (idx == nr_counters_generic)
+                               return -EAGAIN;
+
+                       set_bit(idx, cpuc->used);
+                       hwc->idx = idx;
+               }
+               hwc->config_base  = MSR_ARCH_PERFMON_EVENTSEL0;
+               hwc->counter_base = MSR_ARCH_PERFMON_PERFCTR0;
+       }
 
-       atomic64_counter_set(counter, hwc->prev_count + delta);
+       perf_counters_lapic_init(hwc->nmi);
 
-       /*
-        * Adjust the ->prev_count offset - if we went beyond
-        * irq_period of units, then we got an IRQ and the counter
-        * was set back to -irq_period:
-        */
-       while (delta >= (s64)hwc->irq_period) {
-               hwc->prev_count += hwc->irq_period;
-               delta -= (s64)hwc->irq_period;
-       }
+       __pmc_generic_disable(counter, hwc, idx);
 
+       cpuc->counters[idx] = counter;
        /*
-        * Calculate the next raw counter value we'll write into
-        * the counter at the next sched-in time:
+        * Make it visible before enabling the hw:
         */
-       delta -= (s64)hwc->irq_period;
+       smp_wmb();
+
+       __hw_perf_counter_set_period(counter, hwc, idx);
+       __pmc_generic_enable(counter, hwc, idx);
 
-       hwc->next_count = (s32)delta;
+       return 0;
 }
 
 void perf_counter_print_debug(void)
 {
-       u64 ctrl, status, overflow, pmc_ctrl, pmc_count, next_count;
+       u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
+       struct cpu_hw_counters *cpuc;
        int cpu, idx;
 
-       if (!nr_hw_counters)
+       if (!nr_counters_generic)
                return;
 
        local_irq_disable();
 
        cpu = smp_processor_id();
+       cpuc = &per_cpu(cpu_hw_counters, cpu);
 
        rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
        rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
        rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
+       rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
 
        printk(KERN_INFO "\n");
        printk(KERN_INFO "CPU#%d: ctrl:       %016llx\n", cpu, ctrl);
        printk(KERN_INFO "CPU#%d: status:     %016llx\n", cpu, status);
        printk(KERN_INFO "CPU#%d: overflow:   %016llx\n", cpu, overflow);
+       printk(KERN_INFO "CPU#%d: fixed:      %016llx\n", cpu, fixed);
+       printk(KERN_INFO "CPU#%d: used:       %016llx\n", cpu, *(u64 *)cpuc->used);
 
-       for (idx = 0; idx < nr_hw_counters; idx++) {
+       for (idx = 0; idx < nr_counters_generic; idx++) {
                rdmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + idx, pmc_ctrl);
                rdmsrl(MSR_ARCH_PERFMON_PERFCTR0  + idx, pmc_count);
 
-               next_count = per_cpu(prev_next_count[idx], cpu);
+               prev_left = per_cpu(prev_left[idx], cpu);
 
-               printk(KERN_INFO "CPU#%d: PMC%d ctrl:  %016llx\n",
+               printk(KERN_INFO "CPU#%d:   gen-PMC%d ctrl:  %016llx\n",
                        cpu, idx, pmc_ctrl);
-               printk(KERN_INFO "CPU#%d: PMC%d count: %016llx\n",
+               printk(KERN_INFO "CPU#%d:   gen-PMC%d count: %016llx\n",
+                       cpu, idx, pmc_count);
+               printk(KERN_INFO "CPU#%d:   gen-PMC%d left:  %016llx\n",
+                       cpu, idx, prev_left);
+       }
+       for (idx = 0; idx < nr_counters_fixed; idx++) {
+               rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
+
+               printk(KERN_INFO "CPU#%d: fixed-PMC%d count: %016llx\n",
                        cpu, idx, pmc_count);
-               printk(KERN_INFO "CPU#%d: PMC%d next:  %016llx\n",
-                       cpu, idx, next_count);
        }
        local_irq_enable();
 }
 
-static void x86_perf_counter_disable(struct perf_counter *counter)
+static void pmc_generic_disable(struct perf_counter *counter)
 {
        struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
        struct hw_perf_counter *hwc = &counter->hw;
        unsigned int idx = hwc->idx;
 
-       __x86_perf_counter_disable(hwc, idx);
+       __pmc_generic_disable(counter, hwc, idx);
 
        clear_bit(idx, cpuc->used);
        cpuc->counters[idx] = NULL;
-       __hw_perf_save_counter(counter, hwc, idx);
-}
+       /*
+        * Make sure the cleared pointer becomes visible before we
+        * (potentially) free the counter:
+        */
+       smp_wmb();
 
-static void x86_perf_counter_read(struct perf_counter *counter)
-{
-       struct hw_perf_counter *hwc = &counter->hw;
-       unsigned long addr = hwc->counter_base + hwc->idx;
-       s64 offs, val = -1LL;
-       s32 val32;
-
-       /* Careful: NMI might modify the counter offset */
-       do {
-               offs = hwc->prev_count;
-               rdmsrl(addr, val);
-       } while (offs != hwc->prev_count);
-
-       val32 = (s32) val;
-       val = (s64)hwc->irq_period + (s64)val32;
-       atomic64_counter_set(counter, hwc->prev_count + val);
+       /*
+        * Drain the remaining delta count out of a counter
+        * that we are disabling:
+        */
+       x86_perf_counter_update(counter, hwc, idx);
 }
 
 static void perf_store_irq_data(struct perf_counter *counter, u64 data)
@@ -299,58 +438,42 @@ static void perf_store_irq_data(struct perf_counter *counter, u64 data)
 }
 
 /*
- * NMI-safe enable method:
+ * Save and restart an expired counter. Called by NMI contexts,
+ * so it has to be careful about preempting normal counter ops:
  */
 static void perf_save_and_restart(struct perf_counter *counter)
 {
        struct hw_perf_counter *hwc = &counter->hw;
        int idx = hwc->idx;
-       u64 pmc_ctrl;
 
-       rdmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + idx, pmc_ctrl);
+       x86_perf_counter_update(counter, hwc, idx);
+       __hw_perf_counter_set_period(counter, hwc, idx);
 
-       __hw_perf_save_counter(counter, hwc, idx);
-       __hw_perf_counter_set_period(hwc, idx);
-
-       if (pmc_ctrl & ARCH_PERFMON_EVENTSEL0_ENABLE)
-               __x86_perf_counter_enable(hwc, idx);
+       if (counter->state == PERF_COUNTER_STATE_ACTIVE)
+               __pmc_generic_enable(counter, hwc, idx);
 }
 
 static void
 perf_handle_group(struct perf_counter *sibling, u64 *status, u64 *overflown)
 {
        struct perf_counter *counter, *group_leader = sibling->group_leader;
-       int bit;
 
        /*
-        * Store the counter's own timestamp first:
-        */
-       perf_store_irq_data(sibling, sibling->hw_event.type);
-       perf_store_irq_data(sibling, atomic64_counter_read(sibling));
-
-       /*
-        * Then store sibling timestamps (if any):
+        * Store sibling timestamps (if any):
         */
        list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {
-               if (!counter->active) {
-                       /*
-                        * When counter was not in the overflow mask, we have to
-                        * read it from hardware. We read it as well, when it
-                        * has not been read yet and clear the bit in the
-                        * status mask.
-                        */
-                       bit = counter->hw.idx;
-                       if (!test_bit(bit, (unsigned long *) overflown) ||
-                           test_bit(bit, (unsigned long *) status)) {
-                               clear_bit(bit, (unsigned long *) status);
-                               perf_save_and_restart(counter);
-                       }
-               }
+
+               x86_perf_counter_update(counter, &counter->hw, counter->hw.idx);
                perf_store_irq_data(sibling, counter->hw_event.type);
-               perf_store_irq_data(sibling, atomic64_counter_read(counter));
+               perf_store_irq_data(sibling, atomic64_read(&counter->count));
        }
 }
 
+/*
+ * Maximum interrupt frequency of 100KHz per CPU
+ */
+#define PERFMON_MAX_INTERRUPTS 100000/HZ
+
 /*
  * This handler is triggered by the local APIC, so the APIC IRQ handling
  * rules apply:
@@ -358,24 +481,23 @@ perf_handle_group(struct perf_counter *sibling, u64 *status, u64 *overflown)
 static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)
 {
        int bit, cpu = smp_processor_id();
-       u64 ack, status, saved_global;
-       struct cpu_hw_counters *cpuc;
+       u64 ack, status;
+       struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu);
 
-       rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, saved_global);
+       rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
 
        /* Disable counters globally */
-       wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0);
+       wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
        ack_APIC_irq();
 
-       cpuc = &per_cpu(cpu_hw_counters, cpu);
-
        rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
        if (!status)
                goto out;
 
 again:
+       inc_irq_stat(apic_perf_irqs);
        ack = status;
-       for_each_bit(bit, (unsigned long *) &status, nr_hw_counters) {
+       for_each_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
                struct perf_counter *counter = cpuc->counters[bit];
 
                clear_bit(bit, (unsigned long *) &status);
@@ -396,7 +518,7 @@ again:
                }
                /*
                 * From NMI context we cannot call into the scheduler to
-                * do a task wakeup - but we mark these counters as
+                * do a task wakeup - but we mark these generic as
                 * wakeup_pending and initate a wakeup callback:
                 */
                if (nmi) {
@@ -407,7 +529,7 @@ again:
                }
        }
 
-       wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack, 0);
+       wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);
 
        /*
         * Repeat if there is more work to be done:
@@ -417,19 +539,38 @@ again:
                goto again;
 out:
        /*
-        * Restore - do not reenable when global enable is off:
+        * Restore - do not reenable when global enable is off or throttled:
         */
-       wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, saved_global, 0);
+       if (++cpuc->interrupts < PERFMON_MAX_INTERRUPTS)
+               wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
+}
+
+void perf_counter_unthrottle(void)
+{
+       struct cpu_hw_counters *cpuc;
+       u64 global_enable;
+
+       if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+               return;
+
+       if (unlikely(!perf_counters_initialized))
+               return;
+
+       cpuc = &per_cpu(cpu_hw_counters, smp_processor_id());
+       if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) {
+               if (printk_ratelimit())
+                       printk(KERN_WARNING "PERFMON: max interrupts exceeded!\n");
+               wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
+       }
+       rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, global_enable);
+       if (unlikely(cpuc->global_enable && !global_enable))
+               wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
+       cpuc->interrupts = 0;
 }
 
 void smp_perf_counter_interrupt(struct pt_regs *regs)
 {
        irq_enter();
-#ifdef CONFIG_X86_64
-       add_pda(apic_perf_irqs, 1);
-#else
-       per_cpu(irq_stat, smp_processor_id()).apic_perf_irqs++;
-#endif
        apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR);
        __smp_perf_counter_interrupt(regs, 0);
 
@@ -449,7 +590,7 @@ void perf_counter_notify(struct pt_regs *regs)
        cpu = smp_processor_id();
        cpuc = &per_cpu(cpu_hw_counters, cpu);
 
-       for_each_bit(bit, cpuc->used, nr_hw_counters) {
+       for_each_bit(bit, cpuc->used, X86_PMC_IDX_MAX) {
                struct perf_counter *counter = cpuc->counters[bit];
 
                if (!counter)
@@ -464,7 +605,7 @@ void perf_counter_notify(struct pt_regs *regs)
        local_irq_restore(flags);
 }
 
-void __cpuinit perf_counters_lapic_init(int nmi)
+void perf_counters_lapic_init(int nmi)
 {
        u32 apic_val;
 
@@ -502,14 +643,17 @@ perf_counter_nmi_handler(struct notifier_block *self,
 }
 
 static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
-       .notifier_call          = perf_counter_nmi_handler
+       .notifier_call          = perf_counter_nmi_handler,
+       .next                   = NULL,
+       .priority               = 1
 };
 
 void __init init_hw_perf_counters(void)
 {
        union cpuid10_eax eax;
-       unsigned int unused;
        unsigned int ebx;
+       unsigned int unused;
+       union cpuid10_edx edx;
 
        if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
                return;
@@ -518,36 +662,55 @@ void __init init_hw_perf_counters(void)
         * Check whether the Architectural PerfMon supports
         * Branch Misses Retired Event or not.
         */
-       cpuid(10, &(eax.full), &ebx, &unused, &unused);
+       cpuid(10, &eax.full, &ebx, &unused, &edx.full);
        if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED)
                return;
 
        printk(KERN_INFO "Intel Performance Monitoring support detected.\n");
 
-       printk(KERN_INFO "... version:      %d\n", eax.split.version_id);
-       printk(KERN_INFO "... num_counters: %d\n", eax.split.num_counters);
-       nr_hw_counters = eax.split.num_counters;
-       if (nr_hw_counters > MAX_HW_COUNTERS) {
-               nr_hw_counters = MAX_HW_COUNTERS;
+       printk(KERN_INFO "... version:         %d\n", eax.split.version_id);
+       printk(KERN_INFO "... num counters:    %d\n", eax.split.num_counters);
+       nr_counters_generic = eax.split.num_counters;
+       if (nr_counters_generic > X86_PMC_MAX_GENERIC) {
+               nr_counters_generic = X86_PMC_MAX_GENERIC;
                WARN(1, KERN_ERR "hw perf counters %d > max(%d), clipping!",
-                       nr_hw_counters, MAX_HW_COUNTERS);
+                       nr_counters_generic, X86_PMC_MAX_GENERIC);
+       }
+       perf_counter_mask = (1 << nr_counters_generic) - 1;
+       perf_max_counters = nr_counters_generic;
+
+       printk(KERN_INFO "... bit width:       %d\n", eax.split.bit_width);
+       counter_value_mask = (1ULL << eax.split.bit_width) - 1;
+       printk(KERN_INFO "... value mask:      %016Lx\n", counter_value_mask);
+
+       printk(KERN_INFO "... mask length:     %d\n", eax.split.mask_length);
+
+       nr_counters_fixed = edx.split.num_counters_fixed;
+       if (nr_counters_fixed > X86_PMC_MAX_FIXED) {
+               nr_counters_fixed = X86_PMC_MAX_FIXED;
+               WARN(1, KERN_ERR "hw perf counters fixed %d > max(%d), clipping!",
+                       nr_counters_fixed, X86_PMC_MAX_FIXED);
        }
-       perf_counter_mask = (1 << nr_hw_counters) - 1;
-       perf_max_counters = nr_hw_counters;
+       printk(KERN_INFO "... fixed counters:  %d\n", nr_counters_fixed);
+
+       perf_counter_mask |= ((1LL << nr_counters_fixed)-1) << X86_PMC_IDX_FIXED;
 
-       printk(KERN_INFO "... bit_width:    %d\n", eax.split.bit_width);
-       printk(KERN_INFO "... mask_length:  %d\n", eax.split.mask_length);
+       printk(KERN_INFO "... counter mask:    %016Lx\n", perf_counter_mask);
+       perf_counters_initialized = true;
 
        perf_counters_lapic_init(0);
        register_die_notifier(&perf_counter_nmi_notifier);
+}
 
-       perf_counters_initialized = true;
+static void pmc_generic_read(struct perf_counter *counter)
+{
+       x86_perf_counter_update(counter, &counter->hw, counter->hw.idx);
 }
 
 static const struct hw_perf_counter_ops x86_perf_counter_ops = {
-       .hw_perf_counter_enable         = x86_perf_counter_enable,
-       .hw_perf_counter_disable        = x86_perf_counter_disable,
-       .hw_perf_counter_read           = x86_perf_counter_read,
+       .enable         = pmc_generic_enable,
+       .disable        = pmc_generic_disable,
+       .read           = pmc_generic_read,
 };
 
 const struct hw_perf_counter_ops *
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