x86: cpufeature: add Intel features from CPUID and AVX specs

[linux-2.6-omap-h63xx.git] / kernel / sched_clock.c

diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 4b8474c966dc878e22e6924611c9b84f08e52543..204991a0bfa7d707e6da0e5c27b593b81b42ddb8 100644 (file)
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -42,6 +42,8 @@ unsigned long long __attribute__((weak)) sched_clock(void)
        return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
 }
 
+static __read_mostly int sched_clock_running;
+
 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
 
 struct sched_clock_data {
@@ -70,8 +72,6 @@ static inline struct sched_clock_data *cpu_sdc(int cpu)
        return &per_cpu(sched_clock_data, cpu);
 }
 
-static __read_mostly int sched_clock_running;
-
 void sched_clock_init(void)
 {
        u64 ktime_now = ktime_to_ns(ktime_get());
@@ -97,7 +97,7 @@ void sched_clock_init(void)
  *  - filter out backward motion
  *  - use jiffies to generate a min,max window to clip the raw values
  */
-static void __update_sched_clock(struct sched_clock_data *scd, u64 now)
+static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now)
 {
        unsigned long now_jiffies = jiffies;
        long delta_jiffies = now_jiffies - scd->tick_jiffies;
@@ -130,6 +130,8 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now)
 
        scd->tick_jiffies = now_jiffies;
        scd->clock = clock;
+
+       return clock;
 }
 
 static void lock_double_clock(struct sched_clock_data *data1,
@@ -147,7 +149,7 @@ static void lock_double_clock(struct sched_clock_data *data1,
 u64 sched_clock_cpu(int cpu)
 {
        struct sched_clock_data *scd = cpu_sdc(cpu);
-       u64 now, clock;
+       u64 now, clock, this_clock, remote_clock;
 
        if (unlikely(!sched_clock_running))
                return 0ull;
@@ -156,27 +158,36 @@ u64 sched_clock_cpu(int cpu)
        now = sched_clock();
 
        if (cpu != raw_smp_processor_id()) {
-               /*
-                * in order to update a remote cpu's clock based on our
-                * unstable raw time rebase it against:
-                *   tick_raw           (offset between raw counters)
-                *   tick_gotd          (tick offset between cpus)
-                */
                struct sched_clock_data *my_scd = this_scd();
 
                lock_double_clock(scd, my_scd);
 
-               now += scd->tick_raw - my_scd->tick_raw;
-               now += my_scd->tick_gtod - scd->tick_gtod;
+               this_clock = __update_sched_clock(my_scd, now);
+               remote_clock = scd->clock;
+
+               /*
+                * Use the opportunity that we have both locks
+                * taken to couple the two clocks: we take the
+                * larger time as the latest time for both
+                * runqueues. (this creates monotonic movement)
+                */
+               if (likely(remote_clock < this_clock)) {
+                       clock = this_clock;
+                       scd->clock = clock;
+               } else {
+                       /*
+                        * Should be rare, but possible:
+                        */
+                       clock = remote_clock;
+                       my_scd->clock = remote_clock;
+               }
 
                __raw_spin_unlock(&my_scd->lock);
        } else {
                __raw_spin_lock(&scd->lock);
+               clock = __update_sched_clock(scd, now);
        }
 
-       __update_sched_clock(scd, now);
-       clock = scd->clock;
-
        __raw_spin_unlock(&scd->lock);
 
        return clock;
@@ -222,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
 void sched_clock_idle_wakeup_event(u64 delta_ns)
 {
        struct sched_clock_data *scd = this_scd();
-       u64 now = sched_clock();
 
        /*
         * Override the previous timestamp and ignore all
@@ -238,6 +248,21 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
 }
 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
 
+#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+void sched_clock_init(void)
+{
+       sched_clock_running = 1;
+}
+
+u64 sched_clock_cpu(int cpu)
+{
+       if (unlikely(!sched_clock_running))
+               return 0;
+
+       return sched_clock();
+}
+
 #endif
 
 unsigned long long cpu_clock(int cpu)