From 0793a61d4df8daeac6492dbf8d2f3e5713caae5e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 4 Dec 2008 20:12:29 +0100 Subject: performance counters: core code Implement the core kernel bits of Performance Counters subsystem. The Linux Performance Counter subsystem provides an abstraction of performance counter hardware capabilities. It provides per task and per CPU counters, and it provides event capabilities on top of those. Performance counters are accessed via special file descriptors. There's one file descriptor per virtual counter used. The special file descriptor is opened via the perf_counter_open() system call: int perf_counter_open(u32 hw_event_type, u32 hw_event_period, u32 record_type, pid_t pid, int cpu); The syscall returns the new fd. The fd can be used via the normal VFS system calls: read() can be used to read the counter, fcntl() can be used to set the blocking mode, etc. Multiple counters can be kept open at a time, and the counters can be poll()ed. See more details in Documentation/perf-counters.txt. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- drivers/char/sysrq.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers') diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index ce0d9da52a8a..52146c2a8d97 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -244,6 +245,7 @@ static void sysrq_handle_showregs(int key, struct tty_struct *tty) struct pt_regs *regs = get_irq_regs(); if (regs) show_regs(regs); + perf_counter_print_debug(); } static struct sysrq_key_op sysrq_showregs_op = { .handler = sysrq_handle_showregs, -- cgit v1.2.3 From 4ac13294e44664bb7edf4daf52edb71e7c6bbe84 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 9 Dec 2008 21:43:39 +0100 Subject: perf counters: protect them against CSTATE transitions Impact: fix rare lost events problem There are CPUs whose performance counters misbehave on CSTATE transitions, so provide a way to just disable/enable them around deep idle methods. (hw_perf_enable_all() is cheap on x86.) Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_counter.c | 14 +++++++++++++- drivers/acpi/processor_idle.c | 8 ++++++++ include/linux/perf_counter.h | 4 ++++ 3 files changed, 25 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 6a93d1f04d97..0a7f3bea2dc6 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -119,10 +120,21 @@ void hw_perf_enable_all(void) wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0); } -void hw_perf_disable_all(void) +void hw_perf_restore_ctrl(u64 ctrl) { + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0); +} +EXPORT_SYMBOL_GPL(hw_perf_restore_ctrl); + +u64 hw_perf_disable_all(void) +{ + u64 ctrl; + + rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0); + return ctrl; } +EXPORT_SYMBOL_GPL(hw_perf_disable_all); static inline void __hw_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 5f8d746a9b81..cca804e6f1dd 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -270,8 +270,11 @@ static atomic_t c3_cpu_count; /* Common C-state entry for C2, C3, .. */ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) { + u64 pctrl; + /* Don't trace irqs off for idle */ stop_critical_timings(); + pctrl = hw_perf_disable_all(); if (cstate->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cstate); @@ -284,6 +287,7 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + hw_perf_restore_ctrl(pctrl); start_critical_timings(); } #endif /* !CONFIG_CPU_IDLE */ @@ -1425,8 +1429,11 @@ static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr, */ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { + u64 pctrl; + /* Don't trace irqs off for idle */ stop_critical_timings(); + pctrl = hw_perf_disable_all(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -1441,6 +1448,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + hw_perf_restore_ctrl(pctrl); start_critical_timings(); } diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 22c4469abf44..5031b5614f25 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -156,6 +156,8 @@ extern void perf_counter_task_tick(struct task_struct *task, int cpu); extern void perf_counter_init_task(struct task_struct *task); extern void perf_counter_notify(struct pt_regs *regs); extern void perf_counter_print_debug(void); +extern void hw_perf_restore_ctrl(u64 ctrl); +extern u64 hw_perf_disable_all(void); #else static inline void perf_counter_task_sched_in(struct task_struct *task, int cpu) { } @@ -166,6 +168,8 @@ perf_counter_task_tick(struct task_struct *task, int cpu) { } static inline void perf_counter_init_task(struct task_struct *task) { } static inline void perf_counter_notify(struct pt_regs *regs) { } static inline void perf_counter_print_debug(void) { } +static inline void hw_perf_restore_ctrl(u64 ctrl) { } +static inline u64 hw_perf_disable_all(void) { return 0; } #endif #endif /* _LINUX_PERF_COUNTER_H */ -- cgit v1.2.3 From 01b2838c4298c5e0d30b4993c195ac34dd9df61e Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 11 Dec 2008 13:45:51 +0100 Subject: perf counters: consolidate hw_perf save/restore APIs Impact: cleanup Rename them to better match up the usual IRQ disable/enable APIs: hw_perf_disable_all() => hw_perf_save_disable() hw_perf_restore_ctrl() => hw_perf_restore() Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_counter.c | 8 ++++---- drivers/acpi/processor_idle.c | 10 +++++----- include/linux/perf_counter.h | 10 +++++----- kernel/perf_counter.c | 16 ++++++++-------- 4 files changed, 22 insertions(+), 22 deletions(-) (limited to 'drivers') diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 43c8e9a38b4e..3e1dbebe22b9 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -118,13 +118,13 @@ void hw_perf_enable_all(void) wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0); } -void hw_perf_restore_ctrl(u64 ctrl) +void hw_perf_restore(u64 ctrl) { wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0); } -EXPORT_SYMBOL_GPL(hw_perf_restore_ctrl); +EXPORT_SYMBOL_GPL(hw_perf_restore); -u64 hw_perf_disable_all(void) +u64 hw_perf_save_disable(void) { u64 ctrl; @@ -132,7 +132,7 @@ u64 hw_perf_disable_all(void) wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0); return ctrl; } -EXPORT_SYMBOL_GPL(hw_perf_disable_all); +EXPORT_SYMBOL_GPL(hw_perf_save_disable); static inline void __x86_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index cca804e6f1dd..a3e66a33b7a2 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -270,11 +270,11 @@ static atomic_t c3_cpu_count; /* Common C-state entry for C2, C3, .. */ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) { - u64 pctrl; + u64 perf_flags; /* Don't trace irqs off for idle */ stop_critical_timings(); - pctrl = hw_perf_disable_all(); + perf_flags = hw_perf_save_disable(); if (cstate->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cstate); @@ -287,7 +287,7 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } - hw_perf_restore_ctrl(pctrl); + hw_perf_restore(perf_flags); start_critical_timings(); } #endif /* !CONFIG_CPU_IDLE */ @@ -1433,7 +1433,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) /* Don't trace irqs off for idle */ stop_critical_timings(); - pctrl = hw_perf_disable_all(); + pctrl = hw_perf_save_disable(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -1448,7 +1448,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } - hw_perf_restore_ctrl(pctrl); + hw_perf_restore(pctrl); start_critical_timings(); } diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 9a1713a1be27..68f6e3ad531f 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -67,7 +67,7 @@ enum perf_counter_record_type { * Hardware event to monitor via a performance monitoring counter: */ struct perf_counter_hw_event { - u64 type; + s64 type; u64 irq_period; u32 record_type; @@ -206,8 +206,8 @@ extern void perf_counter_task_tick(struct task_struct *task, int cpu); extern void perf_counter_init_task(struct task_struct *task); extern void perf_counter_notify(struct pt_regs *regs); extern void perf_counter_print_debug(void); -extern void hw_perf_restore_ctrl(u64 ctrl); -extern u64 hw_perf_disable_all(void); +extern u64 hw_perf_save_disable(void); +extern void hw_perf_restore(u64 ctrl); extern void atomic64_counter_set(struct perf_counter *counter, u64 val64); extern u64 atomic64_counter_read(struct perf_counter *counter); @@ -221,8 +221,8 @@ perf_counter_task_tick(struct task_struct *task, int cpu) { } static inline void perf_counter_init_task(struct task_struct *task) { } static inline void perf_counter_notify(struct pt_regs *regs) { } static inline void perf_counter_print_debug(void) { } -static inline void hw_perf_restore_ctrl(u64 ctrl) { } -static inline u64 hw_perf_disable_all(void) { return 0; } +static inline void hw_perf_restore(u64 ctrl) { } +static inline u64 hw_perf_save_disable(void) { return 0; } #endif #endif /* _LINUX_PERF_COUNTER_H */ diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 506286e5ba63..0e93fea17120 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -43,8 +43,8 @@ hw_perf_counter_init(struct perf_counter *counter) return ERR_PTR(-EINVAL); } -u64 __weak hw_perf_disable_all(void) { return 0; } -void __weak hw_perf_restore_ctrl(u64 ctrl) { } +u64 __weak hw_perf_save_disable(void) { return 0; } +void __weak hw_perf_restore(u64 ctrl) { } void __weak hw_perf_counter_setup(void) { } #if BITS_PER_LONG == 64 @@ -180,9 +180,9 @@ static void __perf_counter_remove_from_context(void *info) * Protect the list operation against NMI by disabling the * counters on a global level. NOP for non NMI based counters. */ - perf_flags = hw_perf_disable_all(); + perf_flags = hw_perf_save_disable(); list_del_counter(counter, ctx); - hw_perf_restore_ctrl(perf_flags); + hw_perf_restore(perf_flags); if (!ctx->task) { /* @@ -273,9 +273,9 @@ static void __perf_install_in_context(void *info) * Protect the list operation against NMI by disabling the * counters on a global level. NOP for non NMI based counters. */ - perf_flags = hw_perf_disable_all(); + perf_flags = hw_perf_save_disable(); list_add_counter(counter, ctx); - hw_perf_restore_ctrl(perf_flags); + hw_perf_restore(perf_flags); ctx->nr_counters++; @@ -495,13 +495,13 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu) /* * Rotate the first entry last (works just fine for group counters too): */ - perf_flags = hw_perf_disable_all(); + perf_flags = hw_perf_save_disable(); list_for_each_entry(counter, &ctx->counter_list, list_entry) { list_del(&counter->list_entry); list_add_tail(&counter->list_entry, &ctx->counter_list); break; } - hw_perf_restore_ctrl(perf_flags); + hw_perf_restore(perf_flags); spin_unlock(&ctx->lock); -- cgit v1.2.3 From 37a25424252b6cff4dd4b1937ab6a1dbfcadabcc Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 16 Feb 2009 15:32:23 +0100 Subject: perfcounters: fix acpi_idle_do_entry() workaround Fix merge error in drivers/acpi/processor_idle.c. This resulted in non-working perfcounters on certain Nehalem systems. Signed-off-by: Ingo Molnar --- drivers/acpi/processor_idle.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 259f6e806314..08def2f20cd9 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -826,12 +826,9 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { u64 perf_flags; - u64 pctrl; - /* Don't trace irqs off for idle */ stop_critical_timings(); perf_flags = hw_perf_save_disable(); - pctrl = hw_perf_save_disable(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -847,7 +844,6 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } hw_perf_restore(perf_flags); - hw_perf_restore(pctrl); start_critical_timings(); } -- cgit v1.2.3 From 9e35ad388bea89f7d6f375af4c0ae98803688666 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 13 May 2009 16:21:38 +0200 Subject: perf_counter: Rework the perf counter disable/enable The current disable/enable mechanism is: token = hw_perf_save_disable(); ... /* do bits */ ... hw_perf_restore(token); This works well, provided that the use nests properly. Except we don't. x86 NMI/INT throttling has non-nested use of this, breaking things. Therefore provide a reference counter disable/enable interface, where the first disable disables the hardware, and the last enable enables the hardware again. [ Impact: refactor, simplify the PMU disable/enable logic ] Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/perf_counter.c | 24 ++++---- arch/x86/kernel/cpu/perf_counter.c | 113 ++++++++++++++----------------------- drivers/acpi/processor_idle.c | 6 +- include/linux/perf_counter.h | 10 ++-- kernel/perf_counter.c | 76 +++++++++++++++---------- 5 files changed, 109 insertions(+), 120 deletions(-) (limited to 'drivers') diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c index 15cdc8e67229..bb1b463c1361 100644 --- a/arch/powerpc/kernel/perf_counter.c +++ b/arch/powerpc/kernel/perf_counter.c @@ -386,7 +386,7 @@ static void write_mmcr0(struct cpu_hw_counters *cpuhw, unsigned long mmcr0) * Disable all counters to prevent PMU interrupts and to allow * counters to be added or removed. */ -u64 hw_perf_save_disable(void) +void hw_perf_disable(void) { struct cpu_hw_counters *cpuhw; unsigned long ret; @@ -428,7 +428,6 @@ u64 hw_perf_save_disable(void) mb(); } local_irq_restore(flags); - return ret; } /* @@ -436,7 +435,7 @@ u64 hw_perf_save_disable(void) * If we were previously disabled and counters were added, then * put the new config on the PMU. */ -void hw_perf_restore(u64 disable) +void hw_perf_enable(void) { struct perf_counter *counter; struct cpu_hw_counters *cpuhw; @@ -448,9 +447,12 @@ void hw_perf_restore(u64 disable) int n_lim; int idx; - if (disable) - return; local_irq_save(flags); + if (!cpuhw->disabled) { + local_irq_restore(flags); + return; + } + cpuhw = &__get_cpu_var(cpu_hw_counters); cpuhw->disabled = 0; @@ -649,19 +651,18 @@ int hw_perf_group_sched_in(struct perf_counter *group_leader, /* * Add a counter to the PMU. * If all counters are not already frozen, then we disable and - * re-enable the PMU in order to get hw_perf_restore to do the + * re-enable the PMU in order to get hw_perf_enable to do the * actual work of reconfiguring the PMU. */ static int power_pmu_enable(struct perf_counter *counter) { struct cpu_hw_counters *cpuhw; unsigned long flags; - u64 pmudis; int n0; int ret = -EAGAIN; local_irq_save(flags); - pmudis = hw_perf_save_disable(); + perf_disable(); /* * Add the counter to the list (if there is room) @@ -685,7 +686,7 @@ static int power_pmu_enable(struct perf_counter *counter) ret = 0; out: - hw_perf_restore(pmudis); + perf_enable(); local_irq_restore(flags); return ret; } @@ -697,11 +698,10 @@ static void power_pmu_disable(struct perf_counter *counter) { struct cpu_hw_counters *cpuhw; long i; - u64 pmudis; unsigned long flags; local_irq_save(flags); - pmudis = hw_perf_save_disable(); + perf_disable(); power_pmu_read(counter); @@ -735,7 +735,7 @@ static void power_pmu_disable(struct perf_counter *counter) cpuhw->mmcr[0] &= ~(MMCR0_PMXE | MMCR0_FCECE); } - hw_perf_restore(pmudis); + perf_enable(); local_irq_restore(flags); } diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 7601c014f8f6..313638cecbb5 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -31,7 +31,6 @@ struct cpu_hw_counters { unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; unsigned long interrupts; - u64 throttle_ctrl; int enabled; }; @@ -42,8 +41,8 @@ struct x86_pmu { const char *name; int version; int (*handle_irq)(struct pt_regs *, int); - u64 (*save_disable_all)(void); - void (*restore_all)(u64); + void (*disable_all)(void); + void (*enable_all)(void); void (*enable)(struct hw_perf_counter *, int); void (*disable)(struct hw_perf_counter *, int); unsigned eventsel; @@ -56,6 +55,7 @@ struct x86_pmu { int counter_bits; u64 counter_mask; u64 max_period; + u64 intel_ctrl; }; static struct x86_pmu x86_pmu __read_mostly; @@ -311,22 +311,19 @@ static int __hw_perf_counter_init(struct perf_counter *counter) return 0; } -static u64 intel_pmu_save_disable_all(void) +static void intel_pmu_disable_all(void) { - u64 ctrl; - - rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0); - - return ctrl; } -static u64 amd_pmu_save_disable_all(void) +static void amd_pmu_disable_all(void) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); - int enabled, idx; + int idx; + + if (!cpuc->enabled) + return; - enabled = cpuc->enabled; cpuc->enabled = 0; /* * ensure we write the disable before we start disabling the @@ -334,8 +331,6 @@ static u64 amd_pmu_save_disable_all(void) * right thing. */ barrier(); - if (!enabled) - goto out; for (idx = 0; idx < x86_pmu.num_counters; idx++) { u64 val; @@ -348,37 +343,31 @@ static u64 amd_pmu_save_disable_all(void) val &= ~ARCH_PERFMON_EVENTSEL0_ENABLE; wrmsrl(MSR_K7_EVNTSEL0 + idx, val); } - -out: - return enabled; } -u64 hw_perf_save_disable(void) +void hw_perf_disable(void) { if (!x86_pmu_initialized()) - return 0; - return x86_pmu.save_disable_all(); + return; + return x86_pmu.disable_all(); } -/* - * Exported because of ACPI idle - */ -EXPORT_SYMBOL_GPL(hw_perf_save_disable); -static void intel_pmu_restore_all(u64 ctrl) +static void intel_pmu_enable_all(void) { - wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl); } -static void amd_pmu_restore_all(u64 ctrl) +static void amd_pmu_enable_all(void) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); int idx; - cpuc->enabled = ctrl; - barrier(); - if (!ctrl) + if (cpuc->enabled) return; + cpuc->enabled = 1; + barrier(); + for (idx = 0; idx < x86_pmu.num_counters; idx++) { u64 val; @@ -392,16 +381,12 @@ static void amd_pmu_restore_all(u64 ctrl) } } -void hw_perf_restore(u64 ctrl) +void hw_perf_enable(void) { if (!x86_pmu_initialized()) return; - x86_pmu.restore_all(ctrl); + x86_pmu.enable_all(); } -/* - * Exported because of ACPI idle - */ -EXPORT_SYMBOL_GPL(hw_perf_restore); static inline u64 intel_pmu_get_status(void) { @@ -735,15 +720,14 @@ static int intel_pmu_handle_irq(struct pt_regs *regs, int nmi) int bit, cpu = smp_processor_id(); u64 ack, status; struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu); - int ret = 0; - - cpuc->throttle_ctrl = intel_pmu_save_disable_all(); + perf_disable(); status = intel_pmu_get_status(); - if (!status) - goto out; + if (!status) { + perf_enable(); + return 0; + } - ret = 1; again: inc_irq_stat(apic_perf_irqs); ack = status; @@ -767,19 +751,11 @@ again: status = intel_pmu_get_status(); if (status) goto again; -out: - /* - * Restore - do not reenable when global enable is off or throttled: - */ - if (cpuc->throttle_ctrl) { - if (++cpuc->interrupts < PERFMON_MAX_INTERRUPTS) { - intel_pmu_restore_all(cpuc->throttle_ctrl); - } else { - pr_info("CPU#%d: perfcounters: max interrupt rate exceeded! Throttle on.\n", smp_processor_id()); - } - } - return ret; + if (++cpuc->interrupts != PERFMON_MAX_INTERRUPTS) + perf_enable(); + + return 1; } static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) @@ -792,13 +768,11 @@ static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) struct hw_perf_counter *hwc; int idx, throttle = 0; - cpuc->throttle_ctrl = cpuc->enabled; - cpuc->enabled = 0; - barrier(); - - if (cpuc->throttle_ctrl) { - if (++cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) - throttle = 1; + if (++cpuc->interrupts == PERFMON_MAX_INTERRUPTS) { + throttle = 1; + __perf_disable(); + cpuc->enabled = 0; + barrier(); } for (idx = 0; idx < x86_pmu.num_counters; idx++) { @@ -824,9 +798,6 @@ next: amd_pmu_disable_counter(hwc, idx); } - if (cpuc->throttle_ctrl && !throttle) - cpuc->enabled = 1; - return handled; } @@ -839,13 +810,11 @@ void perf_counter_unthrottle(void) cpuc = &__get_cpu_var(cpu_hw_counters); if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) { - pr_info("CPU#%d: perfcounters: throttle off.\n", smp_processor_id()); - /* * Clear them before re-enabling irqs/NMIs again: */ cpuc->interrupts = 0; - hw_perf_restore(cpuc->throttle_ctrl); + perf_enable(); } else { cpuc->interrupts = 0; } @@ -931,8 +900,8 @@ static __read_mostly struct notifier_block perf_counter_nmi_notifier = { static struct x86_pmu intel_pmu = { .name = "Intel", .handle_irq = intel_pmu_handle_irq, - .save_disable_all = intel_pmu_save_disable_all, - .restore_all = intel_pmu_restore_all, + .disable_all = intel_pmu_disable_all, + .enable_all = intel_pmu_enable_all, .enable = intel_pmu_enable_counter, .disable = intel_pmu_disable_counter, .eventsel = MSR_ARCH_PERFMON_EVENTSEL0, @@ -951,8 +920,8 @@ static struct x86_pmu intel_pmu = { static struct x86_pmu amd_pmu = { .name = "AMD", .handle_irq = amd_pmu_handle_irq, - .save_disable_all = amd_pmu_save_disable_all, - .restore_all = amd_pmu_restore_all, + .disable_all = amd_pmu_disable_all, + .enable_all = amd_pmu_enable_all, .enable = amd_pmu_enable_counter, .disable = amd_pmu_disable_counter, .eventsel = MSR_K7_EVNTSEL0, @@ -1003,6 +972,8 @@ static int intel_pmu_init(void) x86_pmu.counter_bits = eax.split.bit_width; x86_pmu.counter_mask = (1ULL << eax.split.bit_width) - 1; + rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl); + return 0; } diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index d2830f39d46b..9645758c0472 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -763,11 +763,9 @@ static int acpi_idle_bm_check(void) */ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { - u64 perf_flags; - /* Don't trace irqs off for idle */ stop_critical_timings(); - perf_flags = hw_perf_save_disable(); + perf_disable(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -782,7 +780,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } - hw_perf_restore(perf_flags); + perf_enable(); start_critical_timings(); } diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 614f921d616a..e543ecc129f1 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -544,8 +544,10 @@ extern void perf_counter_exit_task(struct task_struct *child); extern void perf_counter_do_pending(void); extern void perf_counter_print_debug(void); extern void perf_counter_unthrottle(void); -extern u64 hw_perf_save_disable(void); -extern void hw_perf_restore(u64 ctrl); +extern void __perf_disable(void); +extern bool __perf_enable(void); +extern void perf_disable(void); +extern void perf_enable(void); extern int perf_counter_task_disable(void); extern int perf_counter_task_enable(void); extern int hw_perf_group_sched_in(struct perf_counter *group_leader, @@ -600,8 +602,8 @@ static inline void perf_counter_exit_task(struct task_struct *child) { } static inline void perf_counter_do_pending(void) { } static inline void perf_counter_print_debug(void) { } static inline void perf_counter_unthrottle(void) { } -static inline void hw_perf_restore(u64 ctrl) { } -static inline u64 hw_perf_save_disable(void) { return 0; } +static inline void perf_disable(void) { } +static inline void perf_enable(void) { } static inline int perf_counter_task_disable(void) { return -EINVAL; } static inline int perf_counter_task_enable(void) { return -EINVAL; } diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 985be0b662af..e814ff04d7ca 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -60,8 +60,9 @@ extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counte return NULL; } -u64 __weak hw_perf_save_disable(void) { return 0; } -void __weak hw_perf_restore(u64 ctrl) { barrier(); } +void __weak hw_perf_disable(void) { barrier(); } +void __weak hw_perf_enable(void) { barrier(); } + void __weak hw_perf_counter_setup(int cpu) { barrier(); } int __weak hw_perf_group_sched_in(struct perf_counter *group_leader, struct perf_cpu_context *cpuctx, @@ -72,6 +73,32 @@ int __weak hw_perf_group_sched_in(struct perf_counter *group_leader, void __weak perf_counter_print_debug(void) { } +static DEFINE_PER_CPU(int, disable_count); + +void __perf_disable(void) +{ + __get_cpu_var(disable_count)++; +} + +bool __perf_enable(void) +{ + return !--__get_cpu_var(disable_count); +} + +void perf_disable(void) +{ + __perf_disable(); + hw_perf_disable(); +} +EXPORT_SYMBOL_GPL(perf_disable); /* ACPI idle */ + +void perf_enable(void) +{ + if (__perf_enable()) + hw_perf_enable(); +} +EXPORT_SYMBOL_GPL(perf_enable); /* ACPI idle */ + static void list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx) { @@ -170,7 +197,6 @@ static void __perf_counter_remove_from_context(void *info) struct perf_counter *counter = info; struct perf_counter_context *ctx = counter->ctx; unsigned long flags; - u64 perf_flags; /* * If this is a task context, we need to check whether it is @@ -191,9 +217,9 @@ static void __perf_counter_remove_from_context(void *info) * Protect the list operation against NMI by disabling the * counters on a global level. NOP for non NMI based counters. */ - perf_flags = hw_perf_save_disable(); + perf_disable(); list_del_counter(counter, ctx); - hw_perf_restore(perf_flags); + perf_enable(); if (!ctx->task) { /* @@ -538,7 +564,6 @@ static void __perf_install_in_context(void *info) struct perf_counter *leader = counter->group_leader; int cpu = smp_processor_id(); unsigned long flags; - u64 perf_flags; int err; /* @@ -556,7 +581,7 @@ static void __perf_install_in_context(void *info) * Protect the list operation against NMI by disabling the * counters on a global level. NOP for non NMI based counters. */ - perf_flags = hw_perf_save_disable(); + perf_disable(); add_counter_to_ctx(counter, ctx); @@ -596,7 +621,7 @@ static void __perf_install_in_context(void *info) cpuctx->max_pertask--; unlock: - hw_perf_restore(perf_flags); + perf_enable(); spin_unlock_irqrestore(&ctx->lock, flags); } @@ -663,7 +688,6 @@ static void __perf_counter_enable(void *info) struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_counter_context *ctx = counter->ctx; struct perf_counter *leader = counter->group_leader; - unsigned long pmuflags; unsigned long flags; int err; @@ -693,14 +717,14 @@ static void __perf_counter_enable(void *info) if (!group_can_go_on(counter, cpuctx, 1)) { err = -EEXIST; } else { - pmuflags = hw_perf_save_disable(); + perf_disable(); if (counter == leader) err = group_sched_in(counter, cpuctx, ctx, smp_processor_id()); else err = counter_sched_in(counter, cpuctx, ctx, smp_processor_id()); - hw_perf_restore(pmuflags); + perf_enable(); } if (err) { @@ -795,7 +819,6 @@ void __perf_counter_sched_out(struct perf_counter_context *ctx, struct perf_cpu_context *cpuctx) { struct perf_counter *counter; - u64 flags; spin_lock(&ctx->lock); ctx->is_active = 0; @@ -803,12 +826,12 @@ void __perf_counter_sched_out(struct perf_counter_context *ctx, goto out; update_context_time(ctx); - flags = hw_perf_save_disable(); + perf_disable(); if (ctx->nr_active) { list_for_each_entry(counter, &ctx->counter_list, list_entry) group_sched_out(counter, cpuctx, ctx); } - hw_perf_restore(flags); + perf_enable(); out: spin_unlock(&ctx->lock); } @@ -860,7 +883,6 @@ __perf_counter_sched_in(struct perf_counter_context *ctx, struct perf_cpu_context *cpuctx, int cpu) { struct perf_counter *counter; - u64 flags; int can_add_hw = 1; spin_lock(&ctx->lock); @@ -870,7 +892,7 @@ __perf_counter_sched_in(struct perf_counter_context *ctx, ctx->timestamp = perf_clock(); - flags = hw_perf_save_disable(); + perf_disable(); /* * First go through the list and put on any pinned groups @@ -917,7 +939,7 @@ __perf_counter_sched_in(struct perf_counter_context *ctx, can_add_hw = 0; } } - hw_perf_restore(flags); + perf_enable(); out: spin_unlock(&ctx->lock); } @@ -955,7 +977,6 @@ int perf_counter_task_disable(void) struct perf_counter_context *ctx = &curr->perf_counter_ctx; struct perf_counter *counter; unsigned long flags; - u64 perf_flags; if (likely(!ctx->nr_counters)) return 0; @@ -969,7 +990,7 @@ int perf_counter_task_disable(void) /* * Disable all the counters: */ - perf_flags = hw_perf_save_disable(); + perf_disable(); list_for_each_entry(counter, &ctx->counter_list, list_entry) { if (counter->state != PERF_COUNTER_STATE_ERROR) { @@ -978,7 +999,7 @@ int perf_counter_task_disable(void) } } - hw_perf_restore(perf_flags); + perf_enable(); spin_unlock_irqrestore(&ctx->lock, flags); @@ -991,7 +1012,6 @@ int perf_counter_task_enable(void) struct perf_counter_context *ctx = &curr->perf_counter_ctx; struct perf_counter *counter; unsigned long flags; - u64 perf_flags; int cpu; if (likely(!ctx->nr_counters)) @@ -1007,7 +1027,7 @@ int perf_counter_task_enable(void) /* * Disable all the counters: */ - perf_flags = hw_perf_save_disable(); + perf_disable(); list_for_each_entry(counter, &ctx->counter_list, list_entry) { if (counter->state > PERF_COUNTER_STATE_OFF) @@ -1017,7 +1037,7 @@ int perf_counter_task_enable(void) ctx->time - counter->total_time_enabled; counter->hw_event.disabled = 0; } - hw_perf_restore(perf_flags); + perf_enable(); spin_unlock(&ctx->lock); @@ -1034,7 +1054,6 @@ int perf_counter_task_enable(void) static void rotate_ctx(struct perf_counter_context *ctx) { struct perf_counter *counter; - u64 perf_flags; if (!ctx->nr_counters) return; @@ -1043,12 +1062,12 @@ static void rotate_ctx(struct perf_counter_context *ctx) /* * Rotate the first entry last (works just fine for group counters too): */ - perf_flags = hw_perf_save_disable(); + perf_disable(); list_for_each_entry(counter, &ctx->counter_list, list_entry) { list_move_tail(&counter->list_entry, &ctx->counter_list); break; } - hw_perf_restore(perf_flags); + perf_enable(); spin_unlock(&ctx->lock); } @@ -3194,7 +3213,6 @@ __perf_counter_exit_task(struct task_struct *child, } else { struct perf_cpu_context *cpuctx; unsigned long flags; - u64 perf_flags; /* * Disable and unlink this counter. @@ -3203,7 +3221,7 @@ __perf_counter_exit_task(struct task_struct *child, * could still be processing it: */ local_irq_save(flags); - perf_flags = hw_perf_save_disable(); + perf_disable(); cpuctx = &__get_cpu_var(perf_cpu_context); @@ -3214,7 +3232,7 @@ __perf_counter_exit_task(struct task_struct *child, child_ctx->nr_counters--; - hw_perf_restore(perf_flags); + perf_enable(); local_irq_restore(flags); } -- cgit v1.2.3 From 251e8e3c7235f5944805a64f24c79fc4696793f1 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 14 May 2009 05:16:59 +0200 Subject: perf_counter: Remove ACPI quirk We had a disable/enable around acpi_idle_do_entry() due to an erratum in an early prototype CPU i had access to. That erratum has been fixed in the BIOS so remove the quirk. The quirk also kept us from profiling interrupts that hit the ACPI idle instruction - so this is an improvement as well, beyond a cleanup and a micro-optimization. [ Impact: improve profiling scope, cleanup, micro-optimization ] Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: Signed-off-by: Ingo Molnar --- drivers/acpi/processor_idle.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 9645758c0472..f7ca8c55956b 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -765,7 +765,6 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { /* Don't trace irqs off for idle */ stop_critical_timings(); - perf_disable(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -780,7 +779,6 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } - perf_enable(); start_critical_timings(); } -- cgit v1.2.3