#include <linux/percpu.h>
#include <linux/rtc.h>
#include <linux/jiffies.h>
+#include <linux/posix-timers.h>
#include <asm/io.h>
#include <asm/processor.h>
unsigned long tb_ticks_per_usec = 100; /* sane default */
EXPORT_SYMBOL(tb_ticks_per_usec);
unsigned long tb_ticks_per_sec;
+EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
u64 tb_to_xs;
unsigned tb_to_us;
*/
DEFINE_PER_CPU(unsigned long, last_jiffy);
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+/*
+ * Factors for converting from cputime_t (timebase ticks) to
+ * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
+ * These are all stored as 0.64 fixed-point binary fractions.
+ */
+u64 __cputime_jiffies_factor;
+EXPORT_SYMBOL(__cputime_jiffies_factor);
+u64 __cputime_msec_factor;
+EXPORT_SYMBOL(__cputime_msec_factor);
+u64 __cputime_sec_factor;
+EXPORT_SYMBOL(__cputime_sec_factor);
+u64 __cputime_clockt_factor;
+EXPORT_SYMBOL(__cputime_clockt_factor);
+
+static void calc_cputime_factors(void)
+{
+ struct div_result res;
+
+ div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_jiffies_factor = res.result_low;
+ div128_by_32(1000, 0, tb_ticks_per_sec, &res);
+ __cputime_msec_factor = res.result_low;
+ div128_by_32(1, 0, tb_ticks_per_sec, &res);
+ __cputime_sec_factor = res.result_low;
+ div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_clockt_factor = res.result_low;
+}
+
+/*
+ * Read the PURR on systems that have it, otherwise the timebase.
+ */
+static u64 read_purr(void)
+{
+ if (cpu_has_feature(CPU_FTR_PURR))
+ return mfspr(SPRN_PURR);
+ return mftb();
+}
+
+/*
+ * Account time for a transition between system, hard irq
+ * or soft irq state.
+ */
+void account_system_vtime(struct task_struct *tsk)
+{
+ u64 now, delta;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ now = read_purr();
+ delta = now - get_paca()->startpurr;
+ get_paca()->startpurr = now;
+ if (!in_interrupt()) {
+ delta += get_paca()->system_time;
+ get_paca()->system_time = 0;
+ }
+ account_system_time(tsk, 0, delta);
+ local_irq_restore(flags);
+}
+
+/*
+ * Transfer the user and system times accumulated in the paca
+ * by the exception entry and exit code to the generic process
+ * user and system time records.
+ * Must be called with interrupts disabled.
+ */
+void account_process_vtime(struct task_struct *tsk)
+{
+ cputime_t utime;
+
+ utime = get_paca()->user_time;
+ get_paca()->user_time = 0;
+ account_user_time(tsk, utime);
+}
+
+static void account_process_time(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ account_process_vtime(current);
+ run_local_timers();
+ if (rcu_pending(cpu))
+ rcu_check_callbacks(cpu, user_mode(regs));
+ scheduler_tick();
+ run_posix_cpu_timers(current);
+}
+
+#ifdef CONFIG_PPC_SPLPAR
+/*
+ * Stuff for accounting stolen time.
+ */
+struct cpu_purr_data {
+ int initialized; /* thread is running */
+ u64 tb0; /* timebase at origin time */
+ u64 purr0; /* PURR at origin time */
+ u64 tb; /* last TB value read */
+ u64 purr; /* last PURR value read */
+ u64 stolen; /* stolen time so far */
+ spinlock_t lock;
+};
+
+static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
+
+static void snapshot_tb_and_purr(void *data)
+{
+ struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
+
+ p->tb0 = mftb();
+ p->purr0 = mfspr(SPRN_PURR);
+ p->tb = p->tb0;
+ p->purr = 0;
+ wmb();
+ p->initialized = 1;
+}
+
+/*
+ * Called during boot when all cpus have come up.
+ */
+void snapshot_timebases(void)
+{
+ int cpu;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ for_each_cpu(cpu)
+ spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock);
+ on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1);
+}
+
+void calculate_steal_time(void)
+{
+ u64 tb, purr, t0;
+ s64 stolen;
+ struct cpu_purr_data *p0, *pme, *phim;
+ int cpu;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ cpu = smp_processor_id();
+ pme = &per_cpu(cpu_purr_data, cpu);
+ if (!pme->initialized)
+ return; /* this can happen in early boot */
+ p0 = &per_cpu(cpu_purr_data, cpu & ~1);
+ phim = &per_cpu(cpu_purr_data, cpu ^ 1);
+ spin_lock(&p0->lock);
+ tb = mftb();
+ purr = mfspr(SPRN_PURR) - pme->purr0;
+ if (!phim->initialized || !cpu_online(cpu ^ 1)) {
+ stolen = (tb - pme->tb) - (purr - pme->purr);
+ } else {
+ t0 = pme->tb0;
+ if (phim->tb0 < t0)
+ t0 = phim->tb0;
+ stolen = phim->tb - t0 - phim->purr - purr - p0->stolen;
+ }
+ if (stolen > 0) {
+ account_steal_time(current, stolen);
+ p0->stolen += stolen;
+ }
+ pme->tb = tb;
+ pme->purr = purr;
+ spin_unlock(&p0->lock);
+}
+
+/*
+ * 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)
+{
+ int cpu;
+ u64 purr;
+ struct cpu_purr_data *p0, *pme, *phim;
+ unsigned long flags;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ cpu = smp_processor_id();
+ pme = &per_cpu(cpu_purr_data, cpu);
+ p0 = &per_cpu(cpu_purr_data, cpu & ~1);
+ phim = &per_cpu(cpu_purr_data, cpu ^ 1);
+ spin_lock_irqsave(&p0->lock, flags);
+ pme->tb = pme->tb0 = mftb();
+ purr = mfspr(SPRN_PURR);
+ if (!phim->initialized) {
+ pme->purr = 0;
+ pme->purr0 = purr;
+ } else {
+ /* set p->purr and p->purr0 for no change in p0->stolen */
+ pme->purr = phim->tb - phim->tb0 - phim->purr - p0->stolen;
+ pme->purr0 = purr - pme->purr;
+ }
+ pme->initialized = 1;
+ spin_unlock_irqrestore(&p0->lock, flags);
+}
+
+#endif /* CONFIG_PPC_SPLPAR */
+
+#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
+#define calc_cputime_factors()
+#define account_process_time(regs) update_process_times(user_mode(regs))
+#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();
+ snapshot_purr();
+}
+
void __delay(unsigned long loops)
{
unsigned long start;
* the two values of tb_update_count match and are even then the
* tb_to_xs and stamp_xsec values are consistent. If not, then it
* loops back and reads them again until this criteria is met.
+ * We expect the caller to have done the first increment of
+ * vdso_data->tb_update_count already.
*/
- ++(vdso_data->tb_update_count);
- smp_wmb();
vdso_data->tb_orig_stamp = new_tb_stamp;
vdso_data->stamp_xsec = new_stamp_xsec;
vdso_data->tb_to_xs = new_tb_to_xs;
unsigned long offset;
u64 new_stamp_xsec;
u64 tlen, t2x;
+ u64 tb, xsec_old, xsec_new;
+ struct gettimeofday_vars *varp;
if (__USE_RTC())
return;
tlen = current_tick_length();
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
- if (tlen == last_tick_len && offset < 0x80000000u) {
- /* check that we're still in sync; if not, resync */
- struct timeval tv;
- __do_gettimeofday(&tv, cur_tb);
- if (tv.tv_sec <= xtime.tv_sec &&
- (tv.tv_sec < xtime.tv_sec ||
- tv.tv_usec * 1000 <= xtime.tv_nsec))
- return;
- }
+ if (tlen == last_tick_len && offset < 0x80000000u)
+ return;
if (tlen != last_tick_len) {
t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs);
last_tick_len = tlen;
new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
do_div(new_stamp_xsec, 1000000000);
new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
+
+ ++vdso_data->tb_update_count;
+ smp_mb();
+
+ /*
+ * Make sure time doesn't go backwards for userspace gettimeofday.
+ */
+ tb = get_tb();
+ varp = do_gtod.varp;
+ xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs)
+ + varp->stamp_xsec;
+ xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec;
+ if (xsec_new < xsec_old)
+ new_stamp_xsec += xsec_old - xsec_new;
+
update_gtod(cur_tb, new_stamp_xsec, t2x);
}
new_tb_ticks_per_jiffy, sign, tick_diff );
tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
tb_ticks_per_sec = new_tb_ticks_per_sec;
+ calc_cputime_factors();
div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
tb_to_xs = divres.result_low;
irq_enter();
profile_tick(CPU_PROFILING, regs);
+ calculate_steal_time();
#ifdef CONFIG_PPC_ISERIES
get_lppaca()->int_dword.fields.decr_int = 0;
* is the case.
*/
if (!cpu_is_offline(cpu))
- update_process_times(user_mode(regs));
+ account_process_time(regs);
/*
* No need to check whether cpu is offline here; boot_cpuid
void __init smp_space_timers(unsigned int max_cpus)
{
int i;
+ unsigned long half = tb_ticks_per_jiffy / 2;
unsigned long offset = tb_ticks_per_jiffy / max_cpus;
unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
/* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
previous_tb -= tb_ticks_per_jiffy;
+ /*
+ * The stolen time calculation for POWER5 shared-processor LPAR
+ * systems works better if the two threads' timebase interrupts
+ * are staggered by half a jiffy with respect to each other.
+ */
for_each_cpu(i) {
- if (i != boot_cpuid) {
+ if (i == boot_cpuid)
+ continue;
+ if (i == (boot_cpuid ^ 1))
+ per_cpu(last_jiffy, i) =
+ per_cpu(last_jiffy, boot_cpuid) - half;
+ else if (i & 1)
+ per_cpu(last_jiffy, i) =
+ per_cpu(last_jiffy, i ^ 1) + half;
+ else {
previous_tb += offset;
per_cpu(last_jiffy, i) = previous_tb;
}
}
#endif
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_mb();
+
/*
* Subtract off the number of nanoseconds since the
* beginning of the last tick.
tb_ticks_per_sec = ppc_tb_freq;
tb_ticks_per_usec = ppc_tb_freq / 1000000;
tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
+ calc_cputime_factors();
/*
* Calculate the length of each tick in ns. It will not be
* It is computed as:
* ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
* where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
- * so as to give the result as a 0.64 fixed-point fraction.
+ * which turns out to be N = 51 - SHIFT_HZ.
+ * This gives the result as a 0.64 fixed-point fraction.
+ * That value is reduced by an offset amounting to 1 xsec per
+ * 2^31 timebase ticks to avoid problems with time going backwards
+ * by 1 xsec when we do timer_recalc_offset due to losing the
+ * fractional xsec. That offset is equal to ppc_tb_freq/2^51
+ * since there are 2^20 xsec in a second.
*/
- div128_by_32(1ULL << (64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT), 0,
- tb_ticks_per_jiffy, &res);
+ div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
+ tb_ticks_per_jiffy << SHIFT_HZ, &res);
div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
ticklen_to_xs = res.result_low;
projects / deliverable / linux.git / commitdiff
