diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 265 |
1 files changed, 262 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9173ea95f91..aa12f36e471 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -80,6 +80,13 @@ struct event_constraint { int weight; }; +struct amd_nb { + int nb_id; /* NorthBridge id */ + int refcnt; /* reference count */ + struct perf_event *owners[X86_PMC_IDX_MAX]; + struct event_constraint event_constraints[X86_PMC_IDX_MAX]; +}; + struct cpu_hw_events { struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */ unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; @@ -92,6 +99,7 @@ struct cpu_hw_events { int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */ u64 tags[X86_PMC_IDX_MAX]; struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */ + struct amd_nb *amd_nb; }; #define __EVENT_CONSTRAINT(c, n, m, w) {\ @@ -153,6 +161,8 @@ struct x86_pmu { static struct x86_pmu x86_pmu __read_mostly; +static raw_spinlock_t amd_nb_lock; + static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, }; @@ -802,7 +812,7 @@ static u64 amd_pmu_event_map(int hw_event) static u64 amd_pmu_raw_event(u64 hw_event) { -#define K7_EVNTSEL_EVENT_MASK 0x7000000FFULL +#define K7_EVNTSEL_EVENT_MASK 0xF000000FFULL #define K7_EVNTSEL_UNIT_MASK 0x00000FF00ULL #define K7_EVNTSEL_EDGE_MASK 0x000040000ULL #define K7_EVNTSEL_INV_MASK 0x000800000ULL @@ -2210,6 +2220,7 @@ perf_event_nmi_handler(struct notifier_block *self, } static struct event_constraint unconstrained; +static struct event_constraint emptyconstraint; static struct event_constraint bts_constraint = EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0); @@ -2249,10 +2260,146 @@ intel_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event return &unconstrained; } +/* + * AMD64 events are detected based on their event codes. + */ +static inline int amd_is_nb_event(struct hw_perf_event *hwc) +{ + return (hwc->config & 0xe0) == 0xe0; +} + +static void amd_put_event_constraints(struct cpu_hw_events *cpuc, + struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + struct amd_nb *nb = cpuc->amd_nb; + int i; + + /* + * only care about NB events + */ + if (!(nb && amd_is_nb_event(hwc))) + return; + + /* + * need to scan whole list because event may not have + * been assigned during scheduling + * + * no race condition possible because event can only + * be removed on one CPU at a time AND PMU is disabled + * when we come here + */ + for (i = 0; i < x86_pmu.num_events; i++) { + if (nb->owners[i] == event) { + cmpxchg(nb->owners+i, event, NULL); + break; + } + } +} + + /* + * AMD64 NorthBridge events need special treatment because + * counter access needs to be synchronized across all cores + * of a package. Refer to BKDG section 3.12 + * + * NB events are events measuring L3 cache, Hypertransport + * traffic. They are identified by an event code >= 0xe00. + * They measure events on the NorthBride which is shared + * by all cores on a package. NB events are counted on a + * shared set of counters. When a NB event is programmed + * in a counter, the data actually comes from a shared + * counter. Thus, access to those counters needs to be + * synchronized. + * + * We implement the synchronization such that no two cores + * can be measuring NB events using the same counters. Thus, + * we maintain a per-NB allocation table. The available slot + * is propagated using the event_constraint structure. + * + * We provide only one choice for each NB event based on + * the fact that only NB events have restrictions. Consequently, + * if a counter is available, there is a guarantee the NB event + * will be assigned to it. If no slot is available, an empty + * constraint is returned and scheduling will eventually fail + * for this event. + * + * Note that all cores attached the same NB compete for the same + * counters to host NB events, this is why we use atomic ops. Some + * multi-chip CPUs may have more than one NB. + * + * Given that resources are allocated (cmpxchg), they must be + * eventually freed for others to use. This is accomplished by + * calling amd_put_event_constraints(). + * + * Non NB events are not impacted by this restriction. + */ static struct event_constraint * amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { - return &unconstrained; + struct hw_perf_event *hwc = &event->hw; + struct amd_nb *nb = cpuc->amd_nb; + struct perf_event *old = NULL; + int max = x86_pmu.num_events; + int i, j, k = -1; + + /* + * if not NB event or no NB, then no constraints + */ + if (!(nb && amd_is_nb_event(hwc))) + return &unconstrained; + + /* + * detect if already present, if so reuse + * + * cannot merge with actual allocation + * because of possible holes + * + * event can already be present yet not assigned (in hwc->idx) + * because of successive calls to x86_schedule_events() from + * hw_perf_group_sched_in() without hw_perf_enable() + */ + for (i = 0; i < max; i++) { + /* + * keep track of first free slot + */ + if (k == -1 && !nb->owners[i]) + k = i; + + /* already present, reuse */ + if (nb->owners[i] == event) + goto done; + } + /* + * not present, so grab a new slot + * starting either at: + */ + if (hwc->idx != -1) { + /* previous assignment */ + i = hwc->idx; + } else if (k != -1) { + /* start from free slot found */ + i = k; + } else { + /* + * event not found, no slot found in + * first pass, try again from the + * beginning + */ + i = 0; + } + j = i; + do { + old = cmpxchg(nb->owners+i, NULL, event); + if (!old) + break; + if (++i == max) + i = 0; + } while (i != j); +done: + if (!old) + return &nb->event_constraints[i]; + + return &emptyconstraint; } static int x86_event_sched_in(struct perf_event *event, @@ -2465,7 +2612,8 @@ static __initconst struct x86_pmu amd_pmu = { .apic = 1, /* use highest bit to detect overflow */ .max_period = (1ULL << 47) - 1, - .get_event_constraints = amd_get_event_constraints + .get_event_constraints = amd_get_event_constraints, + .put_event_constraints = amd_put_event_constraints }; static __init int p6_pmu_init(void) @@ -2589,6 +2737,91 @@ static __init int intel_pmu_init(void) return 0; } +static struct amd_nb *amd_alloc_nb(int cpu, int nb_id) +{ + struct amd_nb *nb; + int i; + + nb = kmalloc(sizeof(struct amd_nb), GFP_KERNEL); + if (!nb) + return NULL; + + memset(nb, 0, sizeof(*nb)); + nb->nb_id = nb_id; + + /* + * initialize all possible NB constraints + */ + for (i = 0; i < x86_pmu.num_events; i++) { + set_bit(i, nb->event_constraints[i].idxmsk); + nb->event_constraints[i].weight = 1; + } + return nb; +} + +static void amd_pmu_cpu_online(int cpu) +{ + struct cpu_hw_events *cpu1, *cpu2; + struct amd_nb *nb = NULL; + int i, nb_id; + + if (boot_cpu_data.x86_max_cores < 2) + return; + + /* + * function may be called too early in the + * boot process, in which case nb_id is bogus + */ + nb_id = amd_get_nb_id(cpu); + if (nb_id == BAD_APICID) + return; + + cpu1 = &per_cpu(cpu_hw_events, cpu); + cpu1->amd_nb = NULL; + + raw_spin_lock(&amd_nb_lock); + + for_each_online_cpu(i) { + cpu2 = &per_cpu(cpu_hw_events, i); + nb = cpu2->amd_nb; + if (!nb) + continue; + if (nb->nb_id == nb_id) + goto found; + } + + nb = amd_alloc_nb(cpu, nb_id); + if (!nb) { + pr_err("perf_events: failed NB allocation for CPU%d\n", cpu); + raw_spin_unlock(&amd_nb_lock); + return; + } +found: + nb->refcnt++; + cpu1->amd_nb = nb; + + raw_spin_unlock(&amd_nb_lock); +} + +static void amd_pmu_cpu_offline(int cpu) +{ + struct cpu_hw_events *cpuhw; + + if (boot_cpu_data.x86_max_cores < 2) + return; + + cpuhw = &per_cpu(cpu_hw_events, cpu); + + raw_spin_lock(&amd_nb_lock); + + if (--cpuhw->amd_nb->refcnt == 0) + kfree(cpuhw->amd_nb); + + cpuhw->amd_nb = NULL; + + raw_spin_unlock(&amd_nb_lock); +} + static __init int amd_pmu_init(void) { /* Performance-monitoring supported from K7 and later: */ @@ -2601,6 +2834,11 @@ static __init int amd_pmu_init(void) memcpy(hw_cache_event_ids, amd_hw_cache_event_ids, sizeof(hw_cache_event_ids)); + /* + * explicitly initialize the boot cpu, other cpus will get + * the cpu hotplug callbacks from smp_init() + */ + amd_pmu_cpu_online(smp_processor_id()); return 0; } @@ -2934,4 +3172,25 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) void hw_perf_event_setup_online(int cpu) { init_debug_store_on_cpu(cpu); + + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + amd_pmu_cpu_online(cpu); + break; + default: + return; + } +} + +void hw_perf_event_setup_offline(int cpu) +{ + init_debug_store_on_cpu(cpu); + + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + amd_pmu_cpu_offline(cpu); + break; + default: + return; + } } |