xnu-3789.60.24.tar.gz

[apple/xnu.git] / osfmk / kern / timer.h

diff --git a/osfmk/kern/timer.h b/osfmk/kern/timer.h
index 9c0fae2883607455f477e6e881fa682a3c7fc93c..a353c6c29b7f336fffb75706c9b615840bcf4982 100644 (file)
--- a/osfmk/kern/timer.h
+++ b/osfmk/kern/timer.h
@@ -59,22 +59,43 @@
 #ifndef        _KERN_TIMER_H_
 #define _KERN_TIMER_H_
 
-#include <stat_time.h>
-
 #include <kern/kern_types.h>
 
+/*
+ * Some platforms have very expensive timebase routines. An optimization
+ * is to avoid switching timers on kernel exit/entry, which results in all
+ * time billed to the system timer. However, when exposed to userspace,
+ * we report as user time to indicate that work was done on behalf of
+ * userspace.
+ *
+ * Although this policy is implemented as a global variable, we snapshot it
+ * at key points in the thread structure (when the thread is locked and
+ * executing in the kernel) to avoid imbalances.
+ */
+extern int precise_user_kernel_time;
+
+/*
+ * thread must be locked, or be the current executing thread, so that
+ * it doesn't transition from user to kernel while updating the
+ * thread-local value (or in kernel debugger context). In the future,
+ * we make take into account task-level or thread-level policy.
+ */
+#define use_precise_user_kernel_time(thread) ( precise_user_kernel_time ) 
+
 /*
  *     Definitions for high resolution timers.  A check
  *     word on the high portion allows atomic updates.
  */
 
 struct timer {
-#if    !STAT_TIME
        uint64_t        tstamp;
-#endif /* STAT_TIME */
+#if    defined(__LP64__)
+       uint64_t        all_bits;
+#else
        uint32_t        low_bits;
        uint32_t        high_bits;
        uint32_t        high_bits_check;
+#endif
 };
 
 typedef struct timer   timer_data_t, *timer_t;
@@ -83,32 +104,6 @@ typedef struct timer        timer_data_t, *timer_t;
  *     Exported kernel interface to timers
  */
 
-#if    STAT_TIME
-
-#include <kern/macro_help.h>
-
-/* Advance a timer by a 32 bit value */
-#define TIMER_BUMP(timer, ticks)                                                               \
-MACRO_BEGIN                                                                                                            \
-       uint32_t        old_low, low;                                                                   \
-                                                                                                                               \
-       old_low = (timer)->low_bits;                                                            \
-       low = old_low + (ticks);                                                                        \
-       if (low < old_low)                                                                                      \
-               timer_update((timer), (timer)->high_bits + 1, low);             \
-       else                                                                                                            \
-               (timer)->low_bits = low;                                                                \
-MACRO_END
-
-#define timer_start(timer, tstamp)
-#define timer_stop(timer, tstamp)
-#define timer_switch(timer, tstamp, new_timer)
-#define thread_timer_event(tstamp, new_timer)
-
-#else  /* STAT_TIME */
-
-#define        TIMER_BUMP(timer, ticks)
-
 /* Start a timer by setting the timestamp */
 extern void            timer_start(
                                        timer_t         timer,
@@ -130,8 +125,6 @@ extern void         thread_timer_event(
                                        uint64_t        tstamp,
                                        timer_t         new_timer);
 
-#endif /* STAT_TIME */
-
 /* Initialize a timer */
 extern void            timer_init(
                                        timer_t         timer);
@@ -151,6 +144,13 @@ extern void                timer_advance(
  */
 
 /* Read timer value */
+#if    defined(__LP64__)
+static inline uint64_t timer_grab(
+                                       timer_t         timer)
+{
+       return timer->all_bits;
+}
+#else
 extern uint64_t        timer_grab(
                                        timer_t         timer);
 
@@ -159,5 +159,6 @@ extern void         timer_update(
                                        timer_t         timer,
                                        uint32_t        new_high,
                                        uint32_t        new_low);
+#endif /* defined(__LP64__) */
 
 #endif /* _KERN_TIMER_H_ */