diff options
Diffstat (limited to 'arch/powerpc/kernel/perf_counter.c')
| -rw-r--r-- | arch/powerpc/kernel/perf_counter.c | 297 |
1 files changed, 262 insertions, 35 deletions
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c index d9bbe5efc649..15cdc8e67229 100644 --- a/arch/powerpc/kernel/perf_counter.c +++ b/arch/powerpc/kernel/perf_counter.c @@ -23,10 +23,14 @@ struct cpu_hw_counters { int n_percpu; int disabled; int n_added; + int n_limited; + u8 pmcs_enabled; struct perf_counter *counter[MAX_HWCOUNTERS]; unsigned int events[MAX_HWCOUNTERS]; + unsigned int flags[MAX_HWCOUNTERS]; u64 mmcr[3]; - u8 pmcs_enabled; + struct perf_counter *limited_counter[MAX_LIMITED_HWCOUNTERS]; + u8 limited_hwidx[MAX_LIMITED_HWCOUNTERS]; }; DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters); @@ -127,7 +131,8 @@ static void write_pmc(int idx, unsigned long val) * and see if any combination of alternative codes is feasible. * The feasible set is returned in event[]. */ -static int power_check_constraints(unsigned int event[], int n_ev) +static int power_check_constraints(unsigned int event[], unsigned int cflags[], + int n_ev) { u64 mask, value, nv; unsigned int alternatives[MAX_HWCOUNTERS][MAX_EVENT_ALTERNATIVES]; @@ -144,11 +149,15 @@ static int power_check_constraints(unsigned int event[], int n_ev) /* First see if the events will go on as-is */ for (i = 0; i < n_ev; ++i) { - alternatives[i][0] = event[i]; + if ((cflags[i] & PPMU_LIMITED_PMC_REQD) + && !ppmu->limited_pmc_event(event[i])) { + ppmu->get_alternatives(event[i], cflags[i], + alternatives[i]); + event[i] = alternatives[i][0]; + } if (ppmu->get_constraint(event[i], &amasks[i][0], &avalues[i][0])) return -1; - choice[i] = 0; } value = mask = 0; for (i = 0; i < n_ev; ++i) { @@ -166,7 +175,9 @@ static int power_check_constraints(unsigned int event[], int n_ev) if (!ppmu->get_alternatives) return -1; for (i = 0; i < n_ev; ++i) { - n_alt[i] = ppmu->get_alternatives(event[i], alternatives[i]); + choice[i] = 0; + n_alt[i] = ppmu->get_alternatives(event[i], cflags[i], + alternatives[i]); for (j = 1; j < n_alt[i]; ++j) ppmu->get_constraint(alternatives[i][j], &amasks[i][j], &avalues[i][j]); @@ -231,28 +242,41 @@ static int power_check_constraints(unsigned int event[], int n_ev) * exclude_{user,kernel,hv} with each other and any previously * added counters. */ -static int check_excludes(struct perf_counter **ctrs, int n_prev, int n_new) +static int check_excludes(struct perf_counter **ctrs, unsigned int cflags[], + int n_prev, int n_new) { - int eu, ek, eh; - int i, n; + int eu = 0, ek = 0, eh = 0; + int i, n, first; struct perf_counter *counter; n = n_prev + n_new; if (n <= 1) return 0; - eu = ctrs[0]->hw_event.exclude_user; - ek = ctrs[0]->hw_event.exclude_kernel; - eh = ctrs[0]->hw_event.exclude_hv; - if (n_prev == 0) - n_prev = 1; - for (i = n_prev; i < n; ++i) { + first = 1; + for (i = 0; i < n; ++i) { + if (cflags[i] & PPMU_LIMITED_PMC_OK) { + cflags[i] &= ~PPMU_LIMITED_PMC_REQD; + continue; + } counter = ctrs[i]; - if (counter->hw_event.exclude_user != eu || - counter->hw_event.exclude_kernel != ek || - counter->hw_event.exclude_hv != eh) + if (first) { + eu = counter->hw_event.exclude_user; + ek = counter->hw_event.exclude_kernel; + eh = counter->hw_event.exclude_hv; + first = 0; + } else if (counter->hw_event.exclude_user != eu || + counter->hw_event.exclude_kernel != ek || + counter->hw_event.exclude_hv != eh) { return -EAGAIN; + } } + + if (eu || ek || eh) + for (i = 0; i < n; ++i) + if (cflags[i] & PPMU_LIMITED_PMC_OK) + cflags[i] |= PPMU_LIMITED_PMC_REQD; + return 0; } @@ -280,6 +304,85 @@ static void power_pmu_read(struct perf_counter *counter) } /* + * On some machines, PMC5 and PMC6 can't be written, don't respect + * the freeze conditions, and don't generate interrupts. This tells + * us if `counter' is using such a PMC. + */ +static int is_limited_pmc(int pmcnum) +{ + return ppmu->limited_pmc5_6 && (pmcnum == 5 || pmcnum == 6); +} + +static void freeze_limited_counters(struct cpu_hw_counters *cpuhw, + unsigned long pmc5, unsigned long pmc6) +{ + struct perf_counter *counter; + u64 val, prev, delta; + int i; + + for (i = 0; i < cpuhw->n_limited; ++i) { + counter = cpuhw->limited_counter[i]; + if (!counter->hw.idx) + continue; + val = (counter->hw.idx == 5) ? pmc5 : pmc6; + prev = atomic64_read(&counter->hw.prev_count); + counter->hw.idx = 0; + delta = (val - prev) & 0xfffffffful; + atomic64_add(delta, &counter->count); + } +} + +static void thaw_limited_counters(struct cpu_hw_counters *cpuhw, + unsigned long pmc5, unsigned long pmc6) +{ + struct perf_counter *counter; + u64 val; + int i; + + for (i = 0; i < cpuhw->n_limited; ++i) { + counter = cpuhw->limited_counter[i]; + counter->hw.idx = cpuhw->limited_hwidx[i]; + val = (counter->hw.idx == 5) ? pmc5 : pmc6; + atomic64_set(&counter->hw.prev_count, val); + perf_counter_update_userpage(counter); + } +} + +/* + * Since limited counters don't respect the freeze conditions, we + * have to read them immediately after freezing or unfreezing the + * other counters. We try to keep the values from the limited + * counters as consistent as possible by keeping the delay (in + * cycles and instructions) between freezing/unfreezing and reading + * the limited counters as small and consistent as possible. + * Therefore, if any limited counters are in use, we read them + * both, and always in the same order, to minimize variability, + * and do it inside the same asm that writes MMCR0. + */ +static void write_mmcr0(struct cpu_hw_counters *cpuhw, unsigned long mmcr0) +{ + unsigned long pmc5, pmc6; + + if (!cpuhw->n_limited) { + mtspr(SPRN_MMCR0, mmcr0); + return; + } + + /* + * Write MMCR0, then read PMC5 and PMC6 immediately. + */ + asm volatile("mtspr %3,%2; mfspr %0,%4; mfspr %1,%5" + : "=&r" (pmc5), "=&r" (pmc6) + : "r" (mmcr0), "i" (SPRN_MMCR0), + "i" (SPRN_PMC5), "i" (SPRN_PMC6)); + + if (mmcr0 & MMCR0_FC) + freeze_limited_counters(cpuhw, pmc5, pmc6); + else + thaw_limited_counters(cpuhw, pmc5, pmc6); +} + +/* * Disable all counters to prevent PMU interrupts and to allow * counters to be added or removed. */ @@ -321,7 +424,7 @@ u64 hw_perf_save_disable(void) * executed and the PMU has frozen the counters * before we return. */ - mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC); + write_mmcr0(cpuhw, mfspr(SPRN_MMCR0) | MMCR0_FC); mb(); } local_irq_restore(flags); @@ -342,6 +445,8 @@ void hw_perf_restore(u64 disable) unsigned long val; s64 left; unsigned int hwc_index[MAX_HWCOUNTERS]; + int n_lim; + int idx; if (disable) return; @@ -414,10 +519,18 @@ void hw_perf_restore(u64 disable) /* * Initialize the PMCs for all the new and moved counters. */ + cpuhw->n_limited = n_lim = 0; for (i = 0; i < cpuhw->n_counters; ++i) { counter = cpuhw->counter[i]; if (counter->hw.idx) continue; + idx = hwc_index[i] + 1; + if (is_limited_pmc(idx)) { + cpuhw->limited_counter[n_lim] = counter; + cpuhw->limited_hwidx[n_lim] = idx; + ++n_lim; + continue; + } val = 0; if (counter->hw_event.irq_period) { left = atomic64_read(&counter->hw.period_left); @@ -425,15 +538,16 @@ void hw_perf_restore(u64 disable) val = 0x80000000L - left; } atomic64_set(&counter->hw.prev_count, val); - counter->hw.idx = hwc_index[i] + 1; - write_pmc(counter->hw.idx, val); + counter->hw.idx = idx; + write_pmc(idx, val); perf_counter_update_userpage(counter); } + cpuhw->n_limited = n_lim; cpuhw->mmcr[0] |= MMCR0_PMXE | MMCR0_FCECE; out_enable: mb(); - mtspr(SPRN_MMCR0, cpuhw->mmcr[0]); + write_mmcr0(cpuhw, cpuhw->mmcr[0]); /* * Enable instruction sampling if necessary @@ -448,7 +562,8 @@ void hw_perf_restore(u64 disable) } static int collect_events(struct perf_counter *group, int max_count, - struct perf_counter *ctrs[], unsigned int *events) + struct perf_counter *ctrs[], unsigned int *events, + unsigned int *flags) { int n = 0; struct perf_counter *counter; @@ -457,6 +572,7 @@ static int collect_events(struct perf_counter *group, int max_count, if (n >= max_count) return -1; ctrs[n] = group; + flags[n] = group->hw.counter_base; events[n++] = group->hw.config; } list_for_each_entry(counter, &group->sibling_list, list_entry) { @@ -465,6 +581,7 @@ static int collect_events(struct perf_counter *group, int max_count, if (n >= max_count) return -1; ctrs[n] = counter; + flags[n] = counter->hw.counter_base; events[n++] = counter->hw.config; } } @@ -497,12 +614,14 @@ int hw_perf_group_sched_in(struct perf_counter *group_leader, cpuhw = &__get_cpu_var(cpu_hw_counters); n0 = cpuhw->n_counters; n = collect_events(group_leader, ppmu->n_counter - n0, - &cpuhw->counter[n0], &cpuhw->events[n0]); + &cpuhw->counter[n0], &cpuhw->events[n0], + &cpuhw->flags[n0]); if (n < 0) return -EAGAIN; - if (check_excludes(cpuhw->counter, n0, n)) + if (check_excludes(cpuhw->counter, cpuhw->flags, n0, n)) return -EAGAIN; - if (power_check_constraints(cpuhw->events, n + n0)) + i = power_check_constraints(cpuhw->events, cpuhw->flags, n + n0); + if (i < 0) return -EAGAIN; cpuhw->n_counters = n0 + n; cpuhw->n_added += n; @@ -554,9 +673,10 @@ static int power_pmu_enable(struct perf_counter *counter) goto out; cpuhw->counter[n0] = counter; cpuhw->events[n0] = counter->hw.config; - if (check_excludes(cpuhw->counter, n0, 1)) + cpuhw->flags[n0] = counter->hw.counter_base; + if (check_excludes(cpuhw->counter, cpuhw->flags, n0, 1)) goto out; - if (power_check_constraints(cpuhw->events, n0 + 1)) + if (power_check_constraints(cpuhw->events, cpuhw->flags, n0 + 1)) goto out; counter->hw.config = cpuhw->events[n0]; @@ -592,12 +712,24 @@ static void power_pmu_disable(struct perf_counter *counter) cpuhw->counter[i-1] = cpuhw->counter[i]; --cpuhw->n_counters; ppmu->disable_pmc(counter->hw.idx - 1, cpuhw->mmcr); - write_pmc(counter->hw.idx, 0); - counter->hw.idx = 0; + if (counter->hw.idx) { + write_pmc(counter->hw.idx, 0); + counter->hw.idx = 0; + } perf_counter_update_userpage(counter); break; } } + for (i = 0; i < cpuhw->n_limited; ++i) + if (counter == cpuhw->limited_counter[i]) + break; + if (i < cpuhw->n_limited) { + while (++i < cpuhw->n_limited) { + cpuhw->limited_counter[i-1] = cpuhw->limited_counter[i]; + cpuhw->limited_hwidx[i-1] = cpuhw->limited_hwidx[i]; + } + --cpuhw->n_limited; + } if (cpuhw->n_counters == 0) { /* disable exceptions if no counters are running */ cpuhw->mmcr[0] &= ~(MMCR0_PMXE | MMCR0_FCECE); @@ -613,6 +745,61 @@ struct pmu power_pmu = { .read = power_pmu_read, }; +/* + * Return 1 if we might be able to put counter on a limited PMC, + * or 0 if not. + * A counter can only go on a limited PMC if it counts something + * that a limited PMC can count, doesn't require interrupts, and + * doesn't exclude any processor mode. + */ +static int can_go_on_limited_pmc(struct perf_counter *counter, unsigned int ev, + unsigned int flags) +{ + int n; + unsigned int alt[MAX_EVENT_ALTERNATIVES]; + + if (counter->hw_event.exclude_user + || counter->hw_event.exclude_kernel + || counter->hw_event.exclude_hv + || counter->hw_event.irq_period) + return 0; + + if (ppmu->limited_pmc_event(ev)) + return 1; + + /* + * The requested event isn't on a limited PMC already; + * see if any alternative code goes on a limited PMC. + */ + if (!ppmu->get_alternatives) + return 0; + + flags |= PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD; + n = ppmu->get_alternatives(ev, flags, alt); + if (n) + return alt[0]; + + return 0; +} + +/* + * Find an alternative event that goes on a normal PMC, if possible, + * and return the event code, or 0 if there is no such alternative. + * (Note: event code 0 is "don't count" on all machines.) + */ +static unsigned long normal_pmc_alternative(unsigned long ev, + unsigned long flags) +{ + unsigned int alt[MAX_EVENT_ALTERNATIVES]; + int n; + + flags &= ~(PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD); + n = ppmu->get_alternatives(ev, flags, alt); + if (!n) + return 0; + return alt[0]; +} + /* Number of perf_counters counting hardware events */ static atomic_t num_counters; /* Used to avoid races in calling reserve/release_pmc_hardware */ @@ -633,9 +820,10 @@ static void hw_perf_counter_destroy(struct perf_counter *counter) const struct pmu *hw_perf_counter_init(struct perf_counter *counter) { - unsigned long ev; + unsigned long ev, flags; struct perf_counter *ctrs[MAX_HWCOUNTERS]; unsigned int events[MAX_HWCOUNTERS]; + unsigned int cflags[MAX_HWCOUNTERS]; int n; int err; @@ -661,7 +849,36 @@ const struct pmu *hw_perf_counter_init(struct perf_counter *counter) */ if (!firmware_has_feature(FW_FEATURE_LPAR)) counter->hw_event.exclude_hv = 0; - + + /* + * If this is a per-task counter, then we can use + * PM_RUN_* events interchangeably with their non RUN_* + * equivalents, e.g. PM_RUN_CYC instead of PM_CYC. + * XXX we should check if the task is an idle task. + */ + flags = 0; + if (counter->ctx->task) + flags |= PPMU_ONLY_COUNT_RUN; + + /* + * If this machine has limited counters, check whether this + * event could go on a limited counter. + */ + if (ppmu->limited_pmc5_6) { + if (can_go_on_limited_pmc(counter, ev, flags)) { + flags |= PPMU_LIMITED_PMC_OK; + } else if (ppmu->limited_pmc_event(ev)) { + /* + * The requested event is on a limited PMC, + * but we can't use a limited PMC; see if any + * alternative goes on a normal PMC. + */ + ev = normal_pmc_alternative(ev, flags); + if (!ev) + return ERR_PTR(-EINVAL); + } + } + /* * If this is in a group, check if it can go on with all the * other hardware counters in the group. We assume the counter @@ -670,18 +887,20 @@ const struct pmu *hw_perf_counter_init(struct perf_counter *counter) n = 0; if (counter->group_leader != counter) { n = collect_events(counter->group_leader, ppmu->n_counter - 1, - ctrs, events); + ctrs, events, cflags); if (n < 0) return ERR_PTR(-EINVAL); } events[n] = ev; ctrs[n] = counter; - if (check_excludes(ctrs, n, 1)) + cflags[n] = flags; + if (check_excludes(ctrs, cflags, n, 1)) return ERR_PTR(-EINVAL); - if (power_check_constraints(events, n + 1)) + if (power_check_constraints(events, cflags, n + 1)) return ERR_PTR(-EINVAL); counter->hw.config = events[n]; + counter->hw.counter_base = cflags[n]; atomic64_set(&counter->hw.period_left, counter->hw_event.irq_period); /* @@ -763,6 +982,10 @@ static void perf_counter_interrupt(struct pt_regs *regs) int found = 0; int nmi; + if (cpuhw->n_limited) + freeze_limited_counters(cpuhw, mfspr(SPRN_PMC5), + mfspr(SPRN_PMC6)); + /* * If interrupts were soft-disabled when this PMU interrupt * occurred, treat it as an NMI. @@ -775,6 +998,8 @@ static void perf_counter_interrupt(struct pt_regs *regs) for (i = 0; i < cpuhw->n_counters; ++i) { counter = cpuhw->counter[i]; + if (is_limited_pmc(counter->hw.idx)) + continue; val = read_pmc(counter->hw.idx); if ((int)val < 0) { /* counter has overflowed */ @@ -791,6 +1016,8 @@ static void perf_counter_interrupt(struct pt_regs *regs) */ if (!found) { for (i = 0; i < ppmu->n_counter; ++i) { + if (is_limited_pmc(i + 1)) + continue; val = read_pmc(i + 1); if ((int)val < 0) write_pmc(i + 1, 0); @@ -804,7 +1031,7 @@ static void perf_counter_interrupt(struct pt_regs *regs) * XXX might want to use MSR.PM to keep the counters frozen until * we get back out of this interrupt. */ - mtspr(SPRN_MMCR0, cpuhw->mmcr[0]); + write_mmcr0(cpuhw, cpuhw->mmcr[0]); if (nmi) nmi_exit(); |