xnu-6153.81.5.tar.gz

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

diff --git a/osfmk/kern/timer.h b/osfmk/kern/timer.h
index abbfcb5e398e3e5441817079a027f836cbfcde88..eeb8eebdb5bcee21fdc976ae4d4eacc8db0a96cb 100644 (file)
--- a/osfmk/kern/timer.h
+++ b/osfmk/kern/timer.h
@@ -2,7 +2,7 @@
  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

- * 
+ *

  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in


@@ -11,10 +11,10 @@
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.

- * 
+ *

  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.

- * 
+ *

  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,


@@ -22,154 +22,142 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.

- * 
+ *

  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * @OSF_COPYRIGHT@
  */
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * @OSF_COPYRIGHT@
  */

-/* 
+/*

  * Mach Operating System
  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  * All Rights Reserved.
  * Mach Operating System
  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  * All Rights Reserved.

- * 
+ *

  * Permission to use, copy, modify and distribute this software and its
  * documentation is hereby granted, provided that both the copyright
  * notice and this permission notice appear in all copies of the
  * software, derivative works or modified versions, and any portions
  * thereof, and that both notices appear in supporting documentation.
  * Permission to use, copy, modify and distribute this software and its
  * documentation is hereby granted, provided that both the copyright
  * notice and this permission notice appear in all copies of the
  * software, derivative works or modified versions, and any portions
  * thereof, and that both notices appear in supporting documentation.

- * 
+ *

  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.

- * 
+ *

  * Carnegie Mellon requests users of this software to return to
  * Carnegie Mellon requests users of this software to return to

- * 
+ *

  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  *  School of Computer Science
  *  Carnegie Mellon University
  *  Pittsburgh PA 15213-3890
  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  *  School of Computer Science
  *  Carnegie Mellon University
  *  Pittsburgh PA 15213-3890

- * 
+ *

  * any improvements or extensions that they make and grant Carnegie Mellon
  * the rights to redistribute these changes.
  */
 /*
  */
 
  * any improvements or extensions that they make and grant Carnegie Mellon
  * the rights to redistribute these changes.
  */
 /*
  */
 

-#ifndef        _KERN_TIMER_H_
+#ifndef _KERN_TIMER_H_

 #define _KERN_TIMER_H_
 
 #define _KERN_TIMER_H_
 

-#include <stat_time.h>
-

 #include <kern/kern_types.h>
 
 /*
 #include <kern/kern_types.h>
 
 /*

- *     Definitions for high resolution timers.  A check
- *     word on the high portion allows atomic updates.
+ * 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;

 
 

-struct timer {
-#if    !STAT_TIME
-       uint64_t        tstamp;
-#endif /* STAT_TIME */
-#if    defined(__LP64__)
-       uint64_t        all_bits;
+/*
+ * 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.
+ */
+
+#if __LP64__
+#define TIMER_ALIGNMENT

 #else
 #else

-       uint32_t        low_bits;
-       uint32_t        high_bits;
-       uint32_t        high_bits_check;
+#define TIMER_ALIGNMENT __attribute__((packed, aligned(4)))

 #endif
 #endif

-};

 
 

-typedef struct timer   timer_data_t, *timer_t;
+struct timer {
+       uint64_t tstamp;
+#if defined(__LP64__)
+       uint64_t all_bits;
+#else /* defined(__LP64__) */
+       /* A check word on the high portion allows atomic updates. */
+       uint32_t low_bits;
+       uint32_t high_bits;
+       uint32_t high_bits_check;
+#endif /* !defined(__LP64__) */
+} TIMER_ALIGNMENT;
+
+typedef struct timer timer_data_t, *timer_t;

 
 /*
 
 /*

- *     Exported kernel interface to timers
+ * Initialize the `timer`.

  */
  */

+void timer_init(timer_t timer);

 
 

-#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,
-                                       uint64_t        tstamp);
-
-/* Stop a timer by updating from the timestamp */
-extern void            timer_stop(
-                                       timer_t         timer,
-                                       uint64_t        tstamp);
-
-/* Update the timer and start a new one */
-extern void            timer_switch(
-                                       timer_t         timer,
-                                       uint64_t        tstamp,
-                                       timer_t         new_timer);
-
-/* Update the thread timer at an event */
-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);
-
-/* Update a saved timer value and return delta to current value */
-extern uint64_t        timer_delta(
-                                       timer_t         timer,
-                                       uint64_t        *save);
-
-/* Advance a timer by a 64 bit value */
-extern void            timer_advance(
-                                       timer_t         timer,
-                                       uint64_t        delta);
+/*
+ * Start the `timer` at time `tstamp`.
+ */
+void timer_start(timer_t timer, uint64_t tstamp);
+
+/*
+ * Stop the `timer` and update it with time `tstamp`.
+ */
+void timer_stop(timer_t timer, uint64_t tstamp);

 
 /*
 
 /*

- *     Exported hardware interface to timers
+ * Update the `timer` at time `tstamp`, leaving it running.

  */
  */

+void timer_update(timer_t timer, uint64_t tstamp);

 
 

-/* Read timer value */
-#if    defined(__LP64__)
-static inline uint64_t timer_grab(
-                                       timer_t         timer)
+/*
+ * Update the `timer` with time `tstamp` and start `new_timer`.
+ */
+void timer_switch(timer_t timer, uint64_t tstamp, timer_t new_timer);
+
+/*
+ * Update the thread timer at an "event," like a context switch, at time
+ * `tstamp`.  This stops the current timer and starts the `new_timer` running.
+ *
+ * Must be called with interrupts disabled.
+ */
+void processor_timer_switch_thread(uint64_t tstamp, timer_t new_timer);
+
+/*
+ * Return the difference between the `timer` and a previous value pointed to by
+ * `prev_in_cur_out`.  Store the current value of the timer to
+ * `prev_in_cur_out`.
+ */
+uint64_t timer_delta(timer_t timer, uint64_t *prev_in_cur_out);
+
+/*
+ * Read the accumulated time of `timer`.
+ */
+#if defined(__LP64__)
+static inline
+uint64_t
+timer_grab(timer_t timer)

 {
        return timer->all_bits;
 }
 {
        return timer->all_bits;
 }

-#else
-extern uint64_t        timer_grab(
-                                       timer_t         timer);
-
-/* Update timer value */
-extern void            timer_update(
-                                       timer_t         timer,
-                                       uint32_t        new_high,
-                                       uint32_t        new_low);
-#endif /* defined(__LP64__) */
+#else /* defined(__LP64__) */
+uint64_t timer_grab(timer_t timer);
+#endif /* !defined(__LP64__) */

 
 

-#endif /* _KERN_TIMER_H_ */
+#endif /* _KERN_TIMER_H_ */