perf_counter: Add P6 PMU support

Add basic P6 PMU support. The P6 uses the EVNTSEL0 EN bit to
enable/disable both its counters. We use this for the
global enable/disable, and clear all config bits (except EN)
to disable individual counters.

Actual ia32 hardware doesn't support lfence, so use a locked
op without side-effect to implement a full barrier.

perf stat and perf record seem to function correctly.

[a.p.zijlstra@chello.nl: cleanups and complete the enable/disable code]

Signed-off-by: Vince Weaver <vince@deater.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <Pine.LNX.4.64.0907081718450.2715@pianoman.cluster.toy>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 36c3dc7..1910f39 100644 (file)
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -65,6 +65,44 @@ static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = {
        .enabled = 1,
 };
 
+/*
+ * Not sure about some of these
+ */
+static const u64 p6_perfmon_event_map[] =
+{
+  [PERF_COUNT_HW_CPU_CYCLES]           = 0x0079,
+  [PERF_COUNT_HW_INSTRUCTIONS]         = 0x00c0,
+  [PERF_COUNT_HW_CACHE_REFERENCES]     = 0x0000,
+  [PERF_COUNT_HW_CACHE_MISSES]         = 0x0000,
+  [PERF_COUNT_HW_BRANCH_INSTRUCTIONS]  = 0x00c4,
+  [PERF_COUNT_HW_BRANCH_MISSES]                = 0x00c5,
+  [PERF_COUNT_HW_BUS_CYCLES]           = 0x0062,
+};
+
+static u64 p6_pmu_event_map(int event)
+{
+       return p6_perfmon_event_map[event];
+}
+
+static u64 p6_pmu_raw_event(u64 event)
+{
+#define P6_EVNTSEL_EVENT_MASK          0x000000FFULL
+#define P6_EVNTSEL_UNIT_MASK           0x0000FF00ULL
+#define P6_EVNTSEL_EDGE_MASK           0x00040000ULL
+#define P6_EVNTSEL_INV_MASK            0x00800000ULL
+#define P6_EVNTSEL_COUNTER_MASK                0xFF000000ULL
+
+#define P6_EVNTSEL_MASK                        \
+       (P6_EVNTSEL_EVENT_MASK |        \
+        P6_EVNTSEL_UNIT_MASK  |        \
+        P6_EVNTSEL_EDGE_MASK  |        \
+        P6_EVNTSEL_INV_MASK   |        \
+        P6_EVNTSEL_COUNTER_MASK)
+
+       return event & P6_EVNTSEL_MASK;
+}
+
+
 /*
  * Intel PerfMon v3. Used on Core2 and later.
  */
@@ -726,6 +764,23 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
        return 0;
 }
 
+static void p6_pmu_disable_all(void)
+{
+       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+       unsigned long val;
+
+       if (!cpuc->enabled)
+               return;
+
+       cpuc->enabled = 0;
+       barrier();
+
+       /* p6 only has one enable register */
+       rdmsrl(MSR_P6_EVNTSEL0, val);
+       val &= ~ARCH_PERFMON_EVENTSEL0_ENABLE;
+       wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
 static void intel_pmu_disable_all(void)
 {
        wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
@@ -767,6 +822,23 @@ void hw_perf_disable(void)
        return x86_pmu.disable_all();
 }
 
+static void p6_pmu_enable_all(void)
+{
+       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+       unsigned long val;
+
+       if (cpuc->enabled)
+               return;
+
+       cpuc->enabled = 1;
+       barrier();
+
+       /* p6 only has one enable register */
+       rdmsrl(MSR_P6_EVNTSEL0, val);
+       val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+       wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
 static void intel_pmu_enable_all(void)
 {
        wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl);
@@ -819,16 +891,13 @@ static inline void intel_pmu_ack_status(u64 ack)
 
 static inline void x86_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
 {
-       int err;
-       err = checking_wrmsrl(hwc->config_base + idx,
+       (void)checking_wrmsrl(hwc->config_base + idx,
                              hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE);
 }
 
 static inline void x86_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
 {
-       int err;
-       err = checking_wrmsrl(hwc->config_base + idx,
-                             hwc->config);
+       (void)checking_wrmsrl(hwc->config_base + idx, hwc->config);
 }
 
 static inline void
@@ -836,13 +905,24 @@ intel_pmu_disable_fixed(struct hw_perf_counter *hwc, int __idx)
 {
        int idx = __idx - X86_PMC_IDX_FIXED;
        u64 ctrl_val, mask;
-       int err;
 
        mask = 0xfULL << (idx * 4);
 
        rdmsrl(hwc->config_base, ctrl_val);
        ctrl_val &= ~mask;
-       err = checking_wrmsrl(hwc->config_base, ctrl_val);
+       (void)checking_wrmsrl(hwc->config_base, ctrl_val);
+}
+
+static inline void
+p6_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
+{
+       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+       unsigned long val = ARCH_PERFMON_EVENTSEL0_ENABLE;
+
+       if (!cpuc->enabled)
+               val = 0;
+
+       (void)checking_wrmsrl(hwc->config_base + idx, val);
 }
 
 static inline void
@@ -943,6 +1023,17 @@ intel_pmu_enable_fixed(struct hw_perf_counter *hwc, int __idx)
        err = checking_wrmsrl(hwc->config_base, ctrl_val);
 }
 
+static void p6_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
+{
+       struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+
+       if (cpuc->enabled)
+               x86_pmu_enable_counter(hwc, idx);
+       else
+               x86_pmu_disable_counter(hwc, idx);
+}
+
+
 static void intel_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
 {
        if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
@@ -1176,6 +1267,49 @@ static void intel_pmu_reset(void)
        local_irq_restore(flags);
 }
 
+static int p6_pmu_handle_irq(struct pt_regs *regs)
+{
+       struct perf_sample_data data;
+       struct cpu_hw_counters *cpuc;
+       struct perf_counter *counter;
+       struct hw_perf_counter *hwc;
+       int idx, handled = 0;
+       u64 val;
+
+       data.regs = regs;
+       data.addr = 0;
+
+       cpuc = &__get_cpu_var(cpu_hw_counters);
+
+       for (idx = 0; idx < x86_pmu.num_counters; idx++) {
+               if (!test_bit(idx, cpuc->active_mask))
+                       continue;
+
+               counter = cpuc->counters[idx];
+               hwc = &counter->hw;
+
+               val = x86_perf_counter_update(counter, hwc, idx);
+               if (val & (1ULL << (x86_pmu.counter_bits - 1)))
+                       continue;
+
+               /*
+                * counter overflow
+                */
+               handled         = 1;
+               data.period     = counter->hw.last_period;
+
+               if (!x86_perf_counter_set_period(counter, hwc, idx))
+                       continue;
+
+               if (perf_counter_overflow(counter, 1, &data))
+                       p6_pmu_disable_counter(hwc, idx);
+       }
+
+       if (handled)
+               inc_irq_stat(apic_perf_irqs);
+
+       return handled;
+}
 
 /*
  * This handler is triggered by the local APIC, so the APIC IRQ handling
@@ -1185,14 +1319,13 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 {
        struct perf_sample_data data;
        struct cpu_hw_counters *cpuc;
-       int bit, cpu, loops;
+       int bit, loops;
        u64 ack, status;
 
        data.regs = regs;
        data.addr = 0;
 
-       cpu = smp_processor_id();
-       cpuc = &per_cpu(cpu_hw_counters, cpu);
+       cpuc = &__get_cpu_var(cpu_hw_counters);
 
        perf_disable();
        status = intel_pmu_get_status();
@@ -1249,14 +1382,13 @@ static int amd_pmu_handle_irq(struct pt_regs *regs)
        struct cpu_hw_counters *cpuc;
        struct perf_counter *counter;
        struct hw_perf_counter *hwc;
-       int cpu, idx, handled = 0;
+       int idx, handled = 0;
        u64 val;
 
        data.regs = regs;
        data.addr = 0;
 
-       cpu = smp_processor_id();
-       cpuc = &per_cpu(cpu_hw_counters, cpu);
+       cpuc = &__get_cpu_var(cpu_hw_counters);
 
        for (idx = 0; idx < x86_pmu.num_counters; idx++) {
                if (!test_bit(idx, cpuc->active_mask))
@@ -1353,6 +1485,32 @@ static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
        .priority               = 1
 };
 
+static struct x86_pmu p6_pmu = {
+       .name                   = "p6",
+       .handle_irq             = p6_pmu_handle_irq,
+       .disable_all            = p6_pmu_disable_all,
+       .enable_all             = p6_pmu_enable_all,
+       .enable                 = p6_pmu_enable_counter,
+       .disable                = p6_pmu_disable_counter,
+       .eventsel               = MSR_P6_EVNTSEL0,
+       .perfctr                = MSR_P6_PERFCTR0,
+       .event_map              = p6_pmu_event_map,
+       .raw_event              = p6_pmu_raw_event,
+       .max_events             = ARRAY_SIZE(p6_perfmon_event_map),
+       .max_period             = (1ULL << 31) - 1,
+       .version                = 0,
+       .num_counters           = 2,
+       /*
+        * Counters have 40 bits implemented. However they are designed such
+        * that bits [32-39] are sign extensions of bit 31. As such the
+        * effective width of a counter for P6-like PMU is 32 bits only.
+        *
+        * See IA-32 Intel Architecture Software developer manual Vol 3B
+        */
+       .counter_bits           = 32,
+       .counter_mask           = (1ULL << 32) - 1,
+};
+
 static struct x86_pmu intel_pmu = {
        .name                   = "Intel",
        .handle_irq             = intel_pmu_handle_irq,
@@ -1392,6 +1550,41 @@ static struct x86_pmu amd_pmu = {
        .max_period             = (1ULL << 47) - 1,
 };
 
+static int p6_pmu_init(void)
+{
+       int high, low;
+
+       switch (boot_cpu_data.x86_model) {
+       case 1:
+       case 3:  /* Pentium Pro */
+       case 5:
+       case 6:  /* Pentium II */
+       case 7:
+       case 8:
+       case 11: /* Pentium III */
+               break;
+       case 9:
+       case 13:
+               /* for Pentium M, we need to check if PMU exist */
+               rdmsr(MSR_IA32_MISC_ENABLE, low, high);
+               if (low & MSR_IA32_MISC_ENABLE_EMON)
+                       break;
+       default:
+               pr_cont("unsupported p6 CPU model %d ",
+                       boot_cpu_data.x86_model);
+               return -ENODEV;
+       }
+
+       if (!cpu_has_apic) {
+               pr_info("no Local APIC, try rebooting with lapic");
+               return -ENODEV;
+       }
+
+       x86_pmu                         = p6_pmu;
+
+       return 0;
+}
+
 static int intel_pmu_init(void)
 {
        union cpuid10_edx edx;
@@ -1400,8 +1593,14 @@ static int intel_pmu_init(void)
        unsigned int ebx;
        int version;
 
-       if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+       if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
+               /* check for P6 processor family */
+          if (boot_cpu_data.x86 == 6) {
+               return p6_pmu_init();
+          } else {
                return -ENODEV;
+          }
+       }
 
        /*
         * Check whether the Architectural PerfMon supports

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 27887c9..53bb955 100644 (file)
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -1,7 +1,13 @@
 #ifndef _PERF_PERF_H
 #define _PERF_PERF_H
 
-#if defined(__x86_64__) || defined(__i386__)
+#if defined(__i386__)
+#include "../../arch/x86/include/asm/unistd.h"
+#define rmb()          asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
+#define cpu_relax()    asm volatile("rep; nop" ::: "memory");
+#endif
+
+#if defined(__x86_64__)
 #include "../../arch/x86/include/asm/unistd.h"
 #define rmb()          asm volatile("lfence" ::: "memory")
 #define cpu_relax()    asm volatile("rep; nop" ::: "memory");