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 776fb5d76c47b5f49981f14a0aef17439c5db7f1..eeb8eebdb5bcee21fdc976ae4d4eacc8db0a96cb 100644 (file)
--- a/osfmk/kern/timer.h
+++ b/osfmk/kern/timer.h
@@ -1,17 +1,20 @@
 /*
 /*

- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

  *
  *

- * @APPLE_LICENSE_HEADER_START@
- * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
- * 

  * 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

- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * 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.
+ *

  * 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,


@@ -19,213 +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_LICENSE_HEADER_END@
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@

  */
 /*
  * @OSF_COPYRIGHT@
  */
  */
 /*
  * @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 <cpus.h>
-#include <stat_time.h>
-
-#include <kern/macro_help.h>

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

-#if    STAT_TIME

 /*
 /*

- *     Statistical timer definitions - use microseconds in timer, seconds
- *     in high unit field.  No adjustment needed to convert to time_value_t
- *     as a result.  Service timers once an hour.
+ * 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;

 
 

-#define TIMER_RATE     1000000
-#define TIMER_HIGH_UNIT        TIMER_RATE
-#undef TIMER_ADJUST
-
-#else  /* STAT_TIME */

 /*
 /*

- *     Machine dependent definitions based on hardware support.
+ * 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.

  */
  */

-
-#include <machine/timer.h>
-
-#endif /* STAT_TIME */
+#define use_precise_user_kernel_time(thread) (precise_user_kernel_time)

 
 /*
 
 /*

- *     Definitions for accurate timers.  high_bits_check is a copy of
- *     high_bits that allows reader to verify that values read are ok.
+ * Definitions for high resolution timers.

  */
 
  */
 

-struct timer {
-       unsigned        low_bits;
-       unsigned        high_bits;
-       unsigned        high_bits_check;
-       unsigned        tstamp;
-};
+#if __LP64__
+#define TIMER_ALIGNMENT
+#else
+#define TIMER_ALIGNMENT __attribute__((packed, aligned(4)))
+#endif

 
 

-typedef struct timer           timer_data_t;
-typedef        struct timer            *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;

 
 /*
 
 /*

- *     Mask to check if low_bits is in danger of overflowing
+ * Initialize the `timer`.

  */
  */

-
-#define        TIMER_LOW_FULL  0x80000000
+void timer_init(timer_t timer);

 
 /*
 
 /*

- *     Kernel timers and current timer array.  [Exported]
+ * Start the `timer` at time `tstamp`.

  */
  */

-
-extern timer_t         current_timer[NCPUS];
-extern timer_data_t    kernel_timer[NCPUS];
+void timer_start(timer_t timer, uint64_t tstamp);

 
 /*
 
 /*

- *     save structure for timer readings.  This is used to save timer
- *     readings for elapsed time computations.
+ * Stop the `timer` and update it with time `tstamp`.

  */
  */

-
-struct timer_save {
-       unsigned        low;
-       unsigned        high;
-};
-
-typedef struct timer_save      timer_save_data_t, *timer_save_t;
+void timer_stop(timer_t timer, uint64_t tstamp);

 
 /*
 
 /*

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

  */
  */

-
-#if    STAT_TIME
-#define start_timer(timer)
-#define timer_switch(timer)
-#else  /* STAT_TIME */
-/* Start timer for this cpu */
-extern void            start_timer(
-                               timer_t         timer);
-
-/* Switch to a new timer */
-extern void            timer_switch(
-                               timer_t         new_timer);
-#endif /* STAT_TIME */
-
-/* Initialize timer module */
-extern void            init_timers(void);
+void timer_update(timer_t timer, uint64_t tstamp);

 
 /*
 
 /*

- * Initializes a single timer.
+ * Update the `timer` with time `tstamp` and start `new_timer`.

  */
  */

-extern void            timer_init(
-                               timer_t this_timer);
-
-/* Normalize timer value */
-extern void            timer_normalize(
-                               timer_t timer);
-
-/* Read value of timer into tv */
-extern void            timer_read(
-                               timer_t timer,
-                               time_value_t *tv);
-
-/* Read thread times */
-extern void            thread_read_times(
-                               thread_t        thread,
-                               time_value_t    *user_time_p,
-                               time_value_t    *system_time_p);
-
-/* Compute timer difference */
-extern unsigned                timer_delta(
-                               timer_t         timer,
-                               timer_save_t    save);
-
-#if    STAT_TIME
-/*
- *     Macro to bump timer values.
- */    
-#define timer_bump(timer, usec)                                        \
-MACRO_BEGIN                                                    \
-       (timer)->low_bits += usec;                              \
-       if ((timer)->low_bits & TIMER_LOW_FULL) {               \
-               timer_normalize(timer);                         \
-       }                                                       \
-MACRO_END
-
-#else  /* STAT_TIME */
+void timer_switch(timer_t timer, uint64_t tstamp, timer_t new_timer);
+

 /*
 /*

- *     Exported hardware interface to timers
+ * 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.

  */
  */

-/* Time trap entry */
-extern void            time_trap_uentry(
-                               unsigned        ts);
-
-/* Time trap exit */
-extern void            time_trap_uexit(
-                               unsigned        ts);
-
-/* Time interrupt entry */
-extern timer_t         time_int_entry(
-                               unsigned        ts,
-                               timer_t         new_timer);
-
-/* Time interrrupt exit */
-extern void            time_int_exit(
-                               unsigned        ts,
-                               timer_t         old_timer);
-
-#endif /* STAT_TIME */
+void processor_timer_switch_thread(uint64_t tstamp, timer_t new_timer);

 
 /*
 
 /*

- *     TIMER_DELTA finds the difference between a timer and a saved value,
- *     and updates the saved value.  Look at high_bits check field after
- *     reading low because that's the first written by a normalize
- *     operation; this isn't necessary for current usage because
- *     this macro is only used when the timer can't be normalized:
- *     thread is not running, or running thread calls it on itself at
- *     splsched().
+ * 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);

 
 

-#define TIMER_DELTA(timer, save, result)                       \
-MACRO_BEGIN                                                    \
-       register unsigned       temp;                           \
-                                                               \
-       temp = (timer).low_bits;                                \
-       if ((save).high != (timer).high_bits_check) {           \
-               result += timer_delta(&(timer), &(save));       \
-       }                                                       \
-       else {                                                  \
-               result += temp - (save).low;                    \
-               (save).low = temp;                              \
-       }                                                       \
-MACRO_END
-
-#endif /* _KERN_TIMER_H_ */
+/*
+ * Read the accumulated time of `timer`.
+ */
+#if defined(__LP64__)
+static inline
+uint64_t
+timer_grab(timer_t timer)
+{
+       return timer->all_bits;
+}
+#else /* defined(__LP64__) */
+uint64_t timer_grab(timer_t timer);
+#endif /* !defined(__LP64__) */
+
+#endif /* _KERN_TIMER_H_ */