diff options
author | David S. Miller <davem@davemloft.net> | 2010-01-20 02:59:47 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2010-01-20 16:23:03 -0800 |
commit | e7bef6b04ca2e8e4cf667c43d7e2ab3034a869d5 (patch) | |
tree | b21d045e0b97f6e3f68a97e992e92432b3f91c2f /arch/sparc | |
parent | 4f6dbe4ac01d2664231d3f3eceadd33a44cde993 (diff) | |
download | op-kernel-dev-e7bef6b04ca2e8e4cf667c43d7e2ab3034a869d5.zip op-kernel-dev-e7bef6b04ca2e8e4cf667c43d7e2ab3034a869d5.tar.gz |
sparc64: Fully support both performance counters.
Add the rest of the conflict detection and resolution logic necessary
to support more than one counter at a time on sparc64.
The structure and implementation closely mimicks that of powerpc.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc')
-rw-r--r-- | arch/sparc/kernel/perf_event.c | 507 |
1 files changed, 353 insertions, 154 deletions
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 2386ac6..e856456 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -55,16 +55,49 @@ #define PIC_UPPER_INDEX 0 #define PIC_LOWER_INDEX 1 +#define PIC_NO_INDEX -1 struct cpu_hw_events { - struct perf_event *events[MAX_HWEVENTS]; - unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)]; - unsigned long active_mask[BITS_TO_LONGS(MAX_HWEVENTS)]; + /* Number of events currently scheduled onto this cpu. + * This tells how many entries in the arrays below + * are valid. + */ + int n_events; + + /* Number of new events added since the last hw_perf_disable(). + * This works because the perf event layer always adds new + * events inside of a perf_{disable,enable}() sequence. + */ + int n_added; + + /* Array of events current scheduled on this cpu. */ + struct perf_event *event[MAX_HWEVENTS]; + + /* Array of encoded longs, specifying the %pcr register + * encoding and the mask of PIC counters this even can + * be scheduled on. See perf_event_encode() et al. + */ + unsigned long events[MAX_HWEVENTS]; + + /* The current counter index assigned to an event. When the + * event hasn't been programmed into the cpu yet, this will + * hold PIC_NO_INDEX. The event->hw.idx value tells us where + * we ought to schedule the event. + */ + int current_idx[MAX_HWEVENTS]; + + /* Software copy of %pcr register on this cpu. */ u64 pcr; + + /* Enabled/disable state. */ int enabled; }; DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, }; +/* An event map describes the characteristics of a performance + * counter event. In particular it gives the encoding as well as + * a mask telling which counters the event can be measured on. + */ struct perf_event_map { u16 encoding; u8 pic_mask; @@ -73,15 +106,20 @@ struct perf_event_map { #define PIC_LOWER 0x02 }; +/* Encode a perf_event_map entry into a long. */ static unsigned long perf_event_encode(const struct perf_event_map *pmap) { return ((unsigned long) pmap->encoding << 16) | pmap->pic_mask; } -static void perf_event_decode(unsigned long val, u16 *enc, u8 *msk) +static u8 perf_event_get_msk(unsigned long val) +{ + return val & 0xff; +} + +static u64 perf_event_get_enc(unsigned long val) { - *msk = val & 0xff; - *enc = val >> 16; + return val >> 16; } #define C(x) PERF_COUNT_HW_CACHE_##x @@ -495,53 +533,6 @@ static inline void sparc_pmu_disable_event(struct cpu_hw_events *cpuc, struct hw pcr_ops->write(cpuc->pcr); } -void hw_perf_enable(void) -{ - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - u64 val; - int i; - - if (cpuc->enabled) - return; - - cpuc->enabled = 1; - barrier(); - - val = cpuc->pcr; - - for (i = 0; i < MAX_HWEVENTS; i++) { - struct perf_event *cp = cpuc->events[i]; - struct hw_perf_event *hwc; - - if (!cp) - continue; - hwc = &cp->hw; - val |= hwc->config_base; - } - - cpuc->pcr = val; - - pcr_ops->write(cpuc->pcr); -} - -void hw_perf_disable(void) -{ - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - u64 val; - - if (!cpuc->enabled) - return; - - cpuc->enabled = 0; - - val = cpuc->pcr; - val &= ~(PCR_UTRACE | PCR_STRACE | - sparc_pmu->hv_bit | sparc_pmu->irq_bit); - cpuc->pcr = val; - - pcr_ops->write(cpuc->pcr); -} - static u32 read_pmc(int idx) { u64 val; @@ -570,6 +561,30 @@ static void write_pmc(int idx, u64 val) write_pic(pic); } +static u64 sparc_perf_event_update(struct perf_event *event, + struct hw_perf_event *hwc, int idx) +{ + int shift = 64 - 32; + u64 prev_raw_count, new_raw_count; + s64 delta; + +again: + prev_raw_count = atomic64_read(&hwc->prev_count); + new_raw_count = read_pmc(idx); + + if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count, + new_raw_count) != prev_raw_count) + goto again; + + delta = (new_raw_count << shift) - (prev_raw_count << shift); + delta >>= shift; + + atomic64_add(delta, &event->count); + atomic64_sub(delta, &hwc->period_left); + + return new_raw_count; +} + static int sparc_perf_event_set_period(struct perf_event *event, struct hw_perf_event *hwc, int idx) { @@ -602,81 +617,166 @@ static int sparc_perf_event_set_period(struct perf_event *event, return ret; } -static int sparc_pmu_enable(struct perf_event *event) +/* If performance event entries have been added, move existing + * events around (if necessary) and then assign new entries to + * counters. + */ +static u64 maybe_change_configuration(struct cpu_hw_events *cpuc, u64 pcr) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - struct hw_perf_event *hwc = &event->hw; - int idx = hwc->idx; + int i; - if (test_and_set_bit(idx, cpuc->used_mask)) - return -EAGAIN; + if (!cpuc->n_added) + goto out; - sparc_pmu_disable_event(cpuc, hwc, idx); + /* Read in the counters which are moving. */ + for (i = 0; i < cpuc->n_events; i++) { + struct perf_event *cp = cpuc->event[i]; - cpuc->events[idx] = event; - set_bit(idx, cpuc->active_mask); + if (cpuc->current_idx[i] != PIC_NO_INDEX && + cpuc->current_idx[i] != cp->hw.idx) { + sparc_perf_event_update(cp, &cp->hw, + cpuc->current_idx[i]); + cpuc->current_idx[i] = PIC_NO_INDEX; + } + } - sparc_perf_event_set_period(event, hwc, idx); - sparc_pmu_enable_event(cpuc, hwc, idx); - perf_event_update_userpage(event); - return 0; + /* Assign to counters all unassigned events. */ + for (i = 0; i < cpuc->n_events; i++) { + struct perf_event *cp = cpuc->event[i]; + struct hw_perf_event *hwc = &cp->hw; + int idx = hwc->idx; + u64 enc; + + if (cpuc->current_idx[i] != PIC_NO_INDEX) + continue; + + sparc_perf_event_set_period(cp, hwc, idx); + cpuc->current_idx[i] = idx; + + enc = perf_event_get_enc(cpuc->events[i]); + pcr |= event_encoding(enc, idx); + } +out: + return pcr; } -static u64 sparc_perf_event_update(struct perf_event *event, - struct hw_perf_event *hwc, int idx) +void hw_perf_enable(void) { - int shift = 64 - 32; - u64 prev_raw_count, new_raw_count; - s64 delta; + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + u64 pcr; -again: - prev_raw_count = atomic64_read(&hwc->prev_count); - new_raw_count = read_pmc(idx); + if (cpuc->enabled) + return; - if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count, - new_raw_count) != prev_raw_count) - goto again; + cpuc->enabled = 1; + barrier(); - delta = (new_raw_count << shift) - (prev_raw_count << shift); - delta >>= shift; + pcr = cpuc->pcr; + if (!cpuc->n_events) { + pcr = 0; + } else { + pcr = maybe_change_configuration(cpuc, pcr); - atomic64_add(delta, &event->count); - atomic64_sub(delta, &hwc->period_left); + /* We require that all of the events have the same + * configuration, so just fetch the settings from the + * first entry. + */ + cpuc->pcr = pcr | cpuc->event[0]->hw.config_base; + } - return new_raw_count; + pcr_ops->write(cpuc->pcr); +} + +void hw_perf_disable(void) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + u64 val; + + if (!cpuc->enabled) + return; + + cpuc->enabled = 0; + cpuc->n_added = 0; + + val = cpuc->pcr; + val &= ~(PCR_UTRACE | PCR_STRACE | + sparc_pmu->hv_bit | sparc_pmu->irq_bit); + cpuc->pcr = val; + + pcr_ops->write(cpuc->pcr); } static void sparc_pmu_disable(struct perf_event *event) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; - int idx = hwc->idx; + unsigned long flags; + int i; - clear_bit(idx, cpuc->active_mask); - sparc_pmu_disable_event(cpuc, hwc, idx); + local_irq_save(flags); + perf_disable(); + + for (i = 0; i < cpuc->n_events; i++) { + if (event == cpuc->event[i]) { + int idx = cpuc->current_idx[i]; + + /* Shift remaining entries down into + * the existing slot. + */ + while (++i < cpuc->n_events) { + cpuc->event[i - 1] = cpuc->event[i]; + cpuc->events[i - 1] = cpuc->events[i]; + cpuc->current_idx[i - 1] = + cpuc->current_idx[i]; + } + + /* Absorb the final count and turn off the + * event. + */ + sparc_pmu_disable_event(cpuc, hwc, idx); + barrier(); + sparc_perf_event_update(event, hwc, idx); - barrier(); + perf_event_update_userpage(event); - sparc_perf_event_update(event, hwc, idx); - cpuc->events[idx] = NULL; - clear_bit(idx, cpuc->used_mask); + cpuc->n_events--; + break; + } + } - perf_event_update_userpage(event); + perf_enable(); + local_irq_restore(flags); +} + +static int active_event_index(struct cpu_hw_events *cpuc, + struct perf_event *event) +{ + int i; + + for (i = 0; i < cpuc->n_events; i++) { + if (cpuc->event[i] == event) + break; + } + BUG_ON(i == cpuc->n_events); + return cpuc->current_idx[i]; } static void sparc_pmu_read(struct perf_event *event) { + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + int idx = active_event_index(cpuc, event); struct hw_perf_event *hwc = &event->hw; - sparc_perf_event_update(event, hwc, hwc->idx); + sparc_perf_event_update(event, hwc, idx); } static void sparc_pmu_unthrottle(struct perf_event *event) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + int idx = active_event_index(cpuc, event); struct hw_perf_event *hwc = &event->hw; - sparc_pmu_enable_event(cpuc, hwc, hwc->idx); + sparc_pmu_enable_event(cpuc, hwc, idx); } static atomic_t active_events = ATOMIC_INIT(0); @@ -754,43 +854,75 @@ static void hw_perf_event_destroy(struct perf_event *event) /* Make sure all events can be scheduled into the hardware at * the same time. This is simplified by the fact that we only * need to support 2 simultaneous HW events. + * + * As a side effect, the evts[]->hw.idx values will be assigned + * on success. These are pending indexes. When the events are + * actually programmed into the chip, these values will propagate + * to the per-cpu cpuc->current_idx[] slots, see the code in + * maybe_change_configuration() for details. */ -static int sparc_check_constraints(unsigned long *events, int n_ev) +static int sparc_check_constraints(struct perf_event **evts, + unsigned long *events, int n_ev) { - if (n_ev <= perf_max_events) { - u8 msk1, msk2; - u16 dummy; - - if (n_ev == 1) - return 0; - BUG_ON(n_ev != 2); - perf_event_decode(events[0], &dummy, &msk1); - perf_event_decode(events[1], &dummy, &msk2); - - /* If both events can go on any counter, OK. */ - if (msk1 == (PIC_UPPER | PIC_LOWER) && - msk2 == (PIC_UPPER | PIC_LOWER)) - return 0; - - /* If one event is limited to a specific counter, - * and the other can go on both, OK. - */ - if ((msk1 == PIC_UPPER || msk1 == PIC_LOWER) && - msk2 == (PIC_UPPER | PIC_LOWER)) - return 0; - if ((msk2 == PIC_UPPER || msk2 == PIC_LOWER) && - msk1 == (PIC_UPPER | PIC_LOWER)) - return 0; - - /* If the events are fixed to different counters, OK. */ - if ((msk1 == PIC_UPPER && msk2 == PIC_LOWER) || - (msk1 == PIC_LOWER && msk2 == PIC_UPPER)) - return 0; - - /* Otherwise, there is a conflict. */ + u8 msk0 = 0, msk1 = 0; + int idx0 = 0; + + /* This case is possible when we are invoked from + * hw_perf_group_sched_in(). + */ + if (!n_ev) + return 0; + + if (n_ev > perf_max_events) + return -1; + + msk0 = perf_event_get_msk(events[0]); + if (n_ev == 1) { + if (msk0 & PIC_LOWER) + idx0 = 1; + goto success; + } + BUG_ON(n_ev != 2); + msk1 = perf_event_get_msk(events[1]); + + /* If both events can go on any counter, OK. */ + if (msk0 == (PIC_UPPER | PIC_LOWER) && + msk1 == (PIC_UPPER | PIC_LOWER)) + goto success; + + /* If one event is limited to a specific counter, + * and the other can go on both, OK. + */ + if ((msk0 == PIC_UPPER || msk0 == PIC_LOWER) && + msk1 == (PIC_UPPER | PIC_LOWER)) { + if (msk0 & PIC_LOWER) + idx0 = 1; + goto success; } + if ((msk1 == PIC_UPPER || msk1 == PIC_LOWER) && + msk0 == (PIC_UPPER | PIC_LOWER)) { + if (msk1 & PIC_UPPER) + idx0 = 1; + goto success; + } + + /* If the events are fixed to different counters, OK. */ + if ((msk0 == PIC_UPPER && msk1 == PIC_LOWER) || + (msk0 == PIC_LOWER && msk1 == PIC_UPPER)) { + if (msk0 & PIC_LOWER) + idx0 = 1; + goto success; + } + + /* Otherwise, there is a conflict. */ return -1; + +success: + evts[0]->hw.idx = idx0; + if (n_ev == 2) + evts[1]->hw.idx = idx0 ^ 1; + return 0; } static int check_excludes(struct perf_event **evts, int n_prev, int n_new) @@ -822,7 +954,8 @@ static int check_excludes(struct perf_event **evts, int n_prev, int n_new) } static int collect_events(struct perf_event *group, int max_count, - struct perf_event *evts[], unsigned long *events) + struct perf_event *evts[], unsigned long *events, + int *current_idx) { struct perf_event *event; int n = 0; @@ -831,7 +964,8 @@ static int collect_events(struct perf_event *group, int max_count, if (n >= max_count) return -1; evts[n] = group; - events[n++] = group->hw.event_base; + events[n] = group->hw.event_base; + current_idx[n++] = PIC_NO_INDEX; } list_for_each_entry(event, &group->sibling_list, group_entry) { if (!is_software_event(event) && @@ -839,20 +973,100 @@ static int collect_events(struct perf_event *group, int max_count, if (n >= max_count) return -1; evts[n] = event; - events[n++] = event->hw.event_base; + events[n] = event->hw.event_base; + current_idx[n++] = PIC_NO_INDEX; } } return n; } +static void event_sched_in(struct perf_event *event, int cpu) +{ + event->state = PERF_EVENT_STATE_ACTIVE; + event->oncpu = cpu; + event->tstamp_running += event->ctx->time - event->tstamp_stopped; + if (is_software_event(event)) + event->pmu->enable(event); +} + +int hw_perf_group_sched_in(struct perf_event *group_leader, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, int cpu) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + struct perf_event *sub; + int n0, n; + + if (!sparc_pmu) + return 0; + + n0 = cpuc->n_events; + n = collect_events(group_leader, perf_max_events - n0, + &cpuc->event[n0], &cpuc->events[n0], + &cpuc->current_idx[n0]); + if (n < 0) + return -EAGAIN; + if (check_excludes(cpuc->event, n0, n)) + return -EINVAL; + if (sparc_check_constraints(cpuc->event, cpuc->events, n + n0)) + return -EAGAIN; + cpuc->n_events = n0 + n; + cpuc->n_added += n; + + cpuctx->active_oncpu += n; + n = 1; + event_sched_in(group_leader, cpu); + list_for_each_entry(sub, &group_leader->sibling_list, group_entry) { + if (sub->state != PERF_EVENT_STATE_OFF) { + event_sched_in(sub, cpu); + n++; + } + } + ctx->nr_active += n; + + return 1; +} + +static int sparc_pmu_enable(struct perf_event *event) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + int n0, ret = -EAGAIN; + unsigned long flags; + + local_irq_save(flags); + perf_disable(); + + n0 = cpuc->n_events; + if (n0 >= perf_max_events) + goto out; + + cpuc->event[n0] = event; + cpuc->events[n0] = event->hw.event_base; + cpuc->current_idx[n0] = PIC_NO_INDEX; + + if (check_excludes(cpuc->event, n0, 1)) + goto out; + if (sparc_check_constraints(cpuc->event, cpuc->events, n0 + 1)) + goto out; + + cpuc->n_events++; + cpuc->n_added++; + + ret = 0; +out: + perf_enable(); + local_irq_restore(flags); + return ret; +} + static int __hw_perf_event_init(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; struct perf_event *evts[MAX_HWEVENTS]; struct hw_perf_event *hwc = &event->hw; unsigned long events[MAX_HWEVENTS]; + int current_idx_dmy[MAX_HWEVENTS]; const struct perf_event_map *pmap; - u64 enc; int n; if (atomic_read(&nmi_active) < 0) @@ -869,10 +1083,7 @@ static int __hw_perf_event_init(struct perf_event *event) } else return -EOPNOTSUPP; - /* We save the enable bits in the config_base. So to - * turn off sampling just write 'config', and to enable - * things write 'config | config_base'. - */ + /* We save the enable bits in the config_base. */ hwc->config_base = sparc_pmu->irq_bit; if (!attr->exclude_user) hwc->config_base |= PCR_UTRACE; @@ -883,13 +1094,11 @@ static int __hw_perf_event_init(struct perf_event *event) hwc->event_base = perf_event_encode(pmap); - enc = pmap->encoding; - n = 0; if (event->group_leader != event) { n = collect_events(event->group_leader, perf_max_events - 1, - evts, events); + evts, events, current_idx_dmy); if (n < 0) return -EINVAL; } @@ -899,9 +1108,11 @@ static int __hw_perf_event_init(struct perf_event *event) if (check_excludes(evts, n, 1)) return -EINVAL; - if (sparc_check_constraints(events, n + 1)) + if (sparc_check_constraints(evts, events, n + 1)) return -EINVAL; + hwc->idx = PIC_NO_INDEX; + /* Try to do all error checking before this point, as unwinding * state after grabbing the PMC is difficult. */ @@ -914,15 +1125,6 @@ static int __hw_perf_event_init(struct perf_event *event) atomic64_set(&hwc->period_left, hwc->sample_period); } - if (pmap->pic_mask & PIC_UPPER) { - hwc->idx = PIC_UPPER_INDEX; - enc <<= sparc_pmu->upper_shift; - } else { - hwc->idx = PIC_LOWER_INDEX; - enc <<= sparc_pmu->lower_shift; - } - - hwc->config |= enc; return 0; } @@ -972,7 +1174,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self, struct perf_sample_data data; struct cpu_hw_events *cpuc; struct pt_regs *regs; - int idx; + int i; if (!atomic_read(&active_events)) return NOTIFY_DONE; @@ -1001,13 +1203,12 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self, if (sparc_pmu->irq_bit) pcr_ops->write(cpuc->pcr); - for (idx = 0; idx < MAX_HWEVENTS; idx++) { - struct perf_event *event = cpuc->events[idx]; + for (i = 0; i < cpuc->n_events; i++) { + struct perf_event *event = cpuc->event[i]; + int idx = cpuc->current_idx[i]; struct hw_perf_event *hwc; u64 val; - if (!test_bit(idx, cpuc->active_mask)) - continue; hwc = &event->hw; val = sparc_perf_event_update(event, hwc, idx); if (val & (1ULL << 31)) @@ -1059,10 +1260,8 @@ void __init init_hw_perf_events(void) pr_cont("Supported PMU type is '%s'\n", sparc_pmu_type); - /* All sparc64 PMUs currently have 2 events. But this simple - * driver only supports one active event at a time. - */ - perf_max_events = 1; + /* All sparc64 PMUs currently have 2 events. */ + perf_max_events = 2; register_die_notifier(&perf_event_nmi_notifier); } |