diff options
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r-- | arch/powerpc/kernel/time.c | 340 |
1 files changed, 165 insertions, 175 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index ce53dfa..0104069 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -53,7 +53,7 @@ #include <linux/posix-timers.h> #include <linux/irq.h> #include <linux/delay.h> -#include <linux/perf_event.h> +#include <linux/irq_work.h> #include <asm/trace.h> #include <asm/io.h> @@ -161,10 +161,9 @@ extern struct timezone sys_tz; static long timezone_offset; unsigned long ppc_proc_freq; -EXPORT_SYMBOL(ppc_proc_freq); +EXPORT_SYMBOL_GPL(ppc_proc_freq); unsigned long ppc_tb_freq; - -static DEFINE_PER_CPU(u64, last_jiffy); +EXPORT_SYMBOL_GPL(ppc_tb_freq); #ifdef CONFIG_VIRT_CPU_ACCOUNTING /* @@ -185,6 +184,8 @@ DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); cputime_t cputime_one_jiffy; +void (*dtl_consumer)(struct dtl_entry *, u64); + static void calc_cputime_factors(void) { struct div_result res; @@ -200,62 +201,153 @@ static void calc_cputime_factors(void) } /* - * Read the PURR on systems that have it, otherwise the timebase. + * Read the SPURR on systems that have it, otherwise the PURR, + * or if that doesn't exist return the timebase value passed in. */ -static u64 read_purr(void) +static u64 read_spurr(u64 tb) { + if (cpu_has_feature(CPU_FTR_SPURR)) + return mfspr(SPRN_SPURR); if (cpu_has_feature(CPU_FTR_PURR)) return mfspr(SPRN_PURR); - return mftb(); + return tb; } +#ifdef CONFIG_PPC_SPLPAR + /* - * Read the SPURR on systems that have it, otherwise the purr + * Scan the dispatch trace log and count up the stolen time. + * Should be called with interrupts disabled. */ -static u64 read_spurr(u64 purr) +static u64 scan_dispatch_log(u64 stop_tb) { - /* - * cpus without PURR won't have a SPURR - * We already know the former when we use this, so tell gcc - */ - if (cpu_has_feature(CPU_FTR_PURR) && cpu_has_feature(CPU_FTR_SPURR)) - return mfspr(SPRN_SPURR); - return purr; + u64 i = local_paca->dtl_ridx; + struct dtl_entry *dtl = local_paca->dtl_curr; + struct dtl_entry *dtl_end = local_paca->dispatch_log_end; + struct lppaca *vpa = local_paca->lppaca_ptr; + u64 tb_delta; + u64 stolen = 0; + u64 dtb; + + if (i == vpa->dtl_idx) + return 0; + while (i < vpa->dtl_idx) { + if (dtl_consumer) + dtl_consumer(dtl, i); + dtb = dtl->timebase; + tb_delta = dtl->enqueue_to_dispatch_time + + dtl->ready_to_enqueue_time; + barrier(); + if (i + N_DISPATCH_LOG < vpa->dtl_idx) { + /* buffer has overflowed */ + i = vpa->dtl_idx - N_DISPATCH_LOG; + dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); + continue; + } + if (dtb > stop_tb) + break; + stolen += tb_delta; + ++i; + ++dtl; + if (dtl == dtl_end) + dtl = local_paca->dispatch_log; + } + local_paca->dtl_ridx = i; + local_paca->dtl_curr = dtl; + return stolen; } /* + * Accumulate stolen time by scanning the dispatch trace log. + * Called on entry from user mode. + */ +void accumulate_stolen_time(void) +{ + u64 sst, ust; + + sst = scan_dispatch_log(get_paca()->starttime_user); + ust = scan_dispatch_log(get_paca()->starttime); + get_paca()->system_time -= sst; + get_paca()->user_time -= ust; + get_paca()->stolen_time += ust + sst; +} + +static inline u64 calculate_stolen_time(u64 stop_tb) +{ + u64 stolen = 0; + + if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) { + stolen = scan_dispatch_log(stop_tb); + get_paca()->system_time -= stolen; + } + + stolen += get_paca()->stolen_time; + get_paca()->stolen_time = 0; + return stolen; +} + +#else /* CONFIG_PPC_SPLPAR */ +static inline u64 calculate_stolen_time(u64 stop_tb) +{ + return 0; +} + +#endif /* CONFIG_PPC_SPLPAR */ + +/* * Account time for a transition between system, hard irq * or soft irq state. */ void account_system_vtime(struct task_struct *tsk) { - u64 now, nowscaled, delta, deltascaled, sys_time; + u64 now, nowscaled, delta, deltascaled; unsigned long flags; + u64 stolen, udelta, sys_scaled, user_scaled; local_irq_save(flags); - now = read_purr(); + now = mftb(); nowscaled = read_spurr(now); - delta = now - get_paca()->startpurr; + get_paca()->system_time += now - get_paca()->starttime; + get_paca()->starttime = now; deltascaled = nowscaled - get_paca()->startspurr; - get_paca()->startpurr = now; get_paca()->startspurr = nowscaled; - if (!in_interrupt()) { - /* deltascaled includes both user and system time. - * Hence scale it based on the purr ratio to estimate - * the system time */ - sys_time = get_paca()->system_time; - if (get_paca()->user_time) - deltascaled = deltascaled * sys_time / - (sys_time + get_paca()->user_time); - delta += sys_time; - get_paca()->system_time = 0; + + stolen = calculate_stolen_time(now); + + delta = get_paca()->system_time; + get_paca()->system_time = 0; + udelta = get_paca()->user_time - get_paca()->utime_sspurr; + get_paca()->utime_sspurr = get_paca()->user_time; + + /* + * Because we don't read the SPURR on every kernel entry/exit, + * deltascaled includes both user and system SPURR ticks. + * Apportion these ticks to system SPURR ticks and user + * SPURR ticks in the same ratio as the system time (delta) + * and user time (udelta) values obtained from the timebase + * over the same interval. The system ticks get accounted here; + * the user ticks get saved up in paca->user_time_scaled to be + * used by account_process_tick. + */ + sys_scaled = delta; + user_scaled = udelta; + if (deltascaled != delta + udelta) { + if (udelta) { + sys_scaled = deltascaled * delta / (delta + udelta); + user_scaled = deltascaled - sys_scaled; + } else { + sys_scaled = deltascaled; + } + } + get_paca()->user_time_scaled += user_scaled; + + if (in_irq() || idle_task(smp_processor_id()) != tsk) { + account_system_time(tsk, 0, delta, sys_scaled); + if (stolen) + account_steal_time(stolen); + } else { + account_idle_time(delta + stolen); } - if (in_irq() || idle_task(smp_processor_id()) != tsk) - account_system_time(tsk, 0, delta, deltascaled); - else - account_idle_time(delta); - __get_cpu_var(cputime_last_delta) = delta; - __get_cpu_var(cputime_scaled_last_delta) = deltascaled; local_irq_restore(flags); } EXPORT_SYMBOL_GPL(account_system_vtime); @@ -265,125 +357,26 @@ EXPORT_SYMBOL_GPL(account_system_vtime); * by the exception entry and exit code to the generic process * user and system time records. * Must be called with interrupts disabled. + * Assumes that account_system_vtime() has been called recently + * (i.e. since the last entry from usermode) so that + * get_paca()->user_time_scaled is up to date. */ void account_process_tick(struct task_struct *tsk, int user_tick) { cputime_t utime, utimescaled; utime = get_paca()->user_time; + utimescaled = get_paca()->user_time_scaled; get_paca()->user_time = 0; - utimescaled = cputime_to_scaled(utime); + get_paca()->user_time_scaled = 0; + get_paca()->utime_sspurr = 0; account_user_time(tsk, utime, utimescaled); } -/* - * Stuff for accounting stolen time. - */ -struct cpu_purr_data { - int initialized; /* thread is running */ - u64 tb; /* last TB value read */ - u64 purr; /* last PURR value read */ - u64 spurr; /* last SPURR value read */ -}; - -/* - * Each entry in the cpu_purr_data array is manipulated only by its - * "owner" cpu -- usually in the timer interrupt but also occasionally - * in process context for cpu online. As long as cpus do not touch - * each others' cpu_purr_data, disabling local interrupts is - * sufficient to serialize accesses. - */ -static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); - -static void snapshot_tb_and_purr(void *data) -{ - unsigned long flags; - struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); - - local_irq_save(flags); - p->tb = get_tb_or_rtc(); - p->purr = mfspr(SPRN_PURR); - wmb(); - p->initialized = 1; - local_irq_restore(flags); -} - -/* - * Called during boot when all cpus have come up. - */ -void snapshot_timebases(void) -{ - if (!cpu_has_feature(CPU_FTR_PURR)) - return; - on_each_cpu(snapshot_tb_and_purr, NULL, 1); -} - -/* - * Must be called with interrupts disabled. - */ -void calculate_steal_time(void) -{ - u64 tb, purr; - s64 stolen; - struct cpu_purr_data *pme; - - pme = &__get_cpu_var(cpu_purr_data); - if (!pme->initialized) - return; /* !CPU_FTR_PURR or early in early boot */ - tb = mftb(); - purr = mfspr(SPRN_PURR); - stolen = (tb - pme->tb) - (purr - pme->purr); - if (stolen > 0) { - if (idle_task(smp_processor_id()) != current) - account_steal_time(stolen); - else - account_idle_time(stolen); - } - pme->tb = tb; - pme->purr = purr; -} - -#ifdef CONFIG_PPC_SPLPAR -/* - * Must be called before the cpu is added to the online map when - * a cpu is being brought up at runtime. - */ -static void snapshot_purr(void) -{ - struct cpu_purr_data *pme; - unsigned long flags; - - if (!cpu_has_feature(CPU_FTR_PURR)) - return; - local_irq_save(flags); - pme = &__get_cpu_var(cpu_purr_data); - pme->tb = mftb(); - pme->purr = mfspr(SPRN_PURR); - pme->initialized = 1; - local_irq_restore(flags); -} - -#endif /* CONFIG_PPC_SPLPAR */ - #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ #define calc_cputime_factors() -#define calculate_steal_time() do { } while (0) -#endif - -#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) -#define snapshot_purr() do { } while (0) #endif -/* - * Called when a cpu comes up after the system has finished booting, - * i.e. as a result of a hotplug cpu action. - */ -void snapshot_timebase(void) -{ - __get_cpu_var(last_jiffy) = get_tb_or_rtc(); - snapshot_purr(); -} - void __delay(unsigned long loops) { unsigned long start; @@ -493,60 +486,60 @@ void __init iSeries_time_init_early(void) } #endif /* CONFIG_PPC_ISERIES */ -#ifdef CONFIG_PERF_EVENTS +#ifdef CONFIG_IRQ_WORK /* * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... */ #ifdef CONFIG_PPC64 -static inline unsigned long test_perf_event_pending(void) +static inline unsigned long test_irq_work_pending(void) { unsigned long x; asm volatile("lbz %0,%1(13)" : "=r" (x) - : "i" (offsetof(struct paca_struct, perf_event_pending))); + : "i" (offsetof(struct paca_struct, irq_work_pending))); return x; } -static inline void set_perf_event_pending_flag(void) +static inline void set_irq_work_pending_flag(void) { asm volatile("stb %0,%1(13)" : : "r" (1), - "i" (offsetof(struct paca_struct, perf_event_pending))); + "i" (offsetof(struct paca_struct, irq_work_pending))); } -static inline void clear_perf_event_pending(void) +static inline void clear_irq_work_pending(void) { asm volatile("stb %0,%1(13)" : : "r" (0), - "i" (offsetof(struct paca_struct, perf_event_pending))); + "i" (offsetof(struct paca_struct, irq_work_pending))); } #else /* 32-bit */ -DEFINE_PER_CPU(u8, perf_event_pending); +DEFINE_PER_CPU(u8, irq_work_pending); -#define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1 -#define test_perf_event_pending() __get_cpu_var(perf_event_pending) -#define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0 +#define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1 +#define test_irq_work_pending() __get_cpu_var(irq_work_pending) +#define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0 #endif /* 32 vs 64 bit */ -void set_perf_event_pending(void) +void set_irq_work_pending(void) { preempt_disable(); - set_perf_event_pending_flag(); + set_irq_work_pending_flag(); set_dec(1); preempt_enable(); } -#else /* CONFIG_PERF_EVENTS */ +#else /* CONFIG_IRQ_WORK */ -#define test_perf_event_pending() 0 -#define clear_perf_event_pending() +#define test_irq_work_pending() 0 +#define clear_irq_work_pending() -#endif /* CONFIG_PERF_EVENTS */ +#endif /* CONFIG_IRQ_WORK */ /* * For iSeries shared processors, we have to let the hypervisor @@ -577,28 +570,17 @@ void timer_interrupt(struct pt_regs * regs) * some CPUs will continuue to take decrementer exceptions */ set_dec(DECREMENTER_MAX); -#ifdef CONFIG_PPC32 +#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) if (atomic_read(&ppc_n_lost_interrupts) != 0) do_IRQ(regs); #endif - now = get_tb_or_rtc(); - if (now < decrementer->next_tb) { - /* not time for this event yet */ - now = decrementer->next_tb - now; - if (now <= DECREMENTER_MAX) - set_dec((int)now); - trace_timer_interrupt_exit(regs); - return; - } old_regs = set_irq_regs(regs); irq_enter(); - calculate_steal_time(); - - if (test_perf_event_pending()) { - clear_perf_event_pending(); - perf_event_do_pending(); + if (test_irq_work_pending()) { + clear_irq_work_pending(); + irq_work_run(); } #ifdef CONFIG_PPC_ISERIES @@ -606,8 +588,16 @@ void timer_interrupt(struct pt_regs * regs) get_lppaca()->int_dword.fields.decr_int = 0; #endif - if (evt->event_handler) - evt->event_handler(evt); + now = get_tb_or_rtc(); + if (now >= decrementer->next_tb) { + decrementer->next_tb = ~(u64)0; + if (evt->event_handler) + evt->event_handler(evt); + } else { + now = decrementer->next_tb - now; + if (now <= DECREMENTER_MAX) + set_dec((int)now); + } #ifdef CONFIG_PPC_ISERIES if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |