include/sys/clock_impl.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 #ifndef _SYS_CLOCK_IMPL_H
  27 #define _SYS_CLOCK_IMPL_H
  28
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #if (defined(_KERNEL) || defined(_KMEMUSER))
  34 #include <sys/types.h>
  35 #include <sys/cpuvar.h>
  36 #include <sys/cyclic.h>
  37 #include <sys/time.h>
  38
  39 /*
  40  * Default clock rate in Hz.
  41  */
  42 #define HZ_DEFAULT                      (100)
  43
  44 /*
  45  * Thresholds over which we switch between event and cyclic driven lbolt. The
  46  * current default values were derived experimentally and will keep the
  47  * system on event driven mode when idle and respond to activity around the
  48  * lbolt DDI functions by switching to cyclic mode.
  49  */
  50 #define LBOLT_THRESH_CALLS              (75)
  51 #define LBOLT_THRESH_INTERVAL           (1)
  52
  53 /*
  54  * Both lbolt_cpu_t and lbolt_info_t are cache line sized and aligned,
  55  * please take that in consideration if modifying these.
  56  */
  57 typedef struct lbolt_cpu {
  58         int64_t lbc_counter;    /* number of calls to the DDI lbolt routines */
  59         int64_t lbc_cnt_start;  /* beggining of the cnt interval (in ticks) */
  60         char lbc_pad[CPU_CACHE_COHERENCE_SIZE - (2 * sizeof (int64_t))];
  61 } lbolt_cpu_t;
  62
  63 typedef struct lbolt_info {
  64         union {
  65                 cyclic_id_t lbi_cyclic_id;      /* lbolt's cyclic id */
  66                 int64_t lbi_id_pad;             /* 64bit padding */
  67         } id;
  68         int64_t lbi_thresh_calls;       /* max calls per interval */
  69         int64_t lbi_thresh_interval;    /* interval window for the # of calls */
  70         int64_t lbi_debug_ts;           /* last time we dropped into kmdb */
  71         int64_t lbi_debug_time;         /* time spent in the debugger */
  72         int64_t lbi_internal;           /* lbolt source when on cyclic mode */
  73         uint32_t lbi_token;             /* synchronize cyclic mode switch */
  74         boolean_t lbi_cyc_deactivate;   /* lbolt_cyclic self deactivation */
  75         int64_t lbi_cyc_deac_start;     /* deactivation interval */
  76 } lbolt_info_t;
  77
  78 extern int64_t lbolt_bootstrap(void);
  79 extern int64_t lbolt_event_driven(void);
  80 extern int64_t lbolt_cyclic_driven(void);
  81 extern int64_t (*lbolt_hybrid)(void);
  82 extern uint_t lbolt_ev_to_cyclic(caddr_t, caddr_t);
  83
  84 extern void lbolt_softint_add(void);
  85 extern void lbolt_softint_post(void);
  86
  87 extern void lbolt_debug_entry(void);
  88 extern void lbolt_debug_return(void);
  89
  90 extern lbolt_info_t *lb_info;
  91
  92 /*
  93  * LBOLT_WAITFREE{,64} provide a non-waiting version of lbolt.
  94  */
  95 #define LBOLT_WAITFREE64                                                \
  96         (lbolt_hybrid == lbolt_bootstrap ? 0 :                          \
  97         (lbolt_hybrid == lbolt_event_driven ?                           \
  98             ((gethrtime_waitfree()/nsec_per_tick) -                     \
  99             lb_info->lbi_debug_time) :                                  \
 100             (lb_info->lbi_internal - lb_info->lbi_debug_time)))
 101
 102 #define LBOLT_WAITFREE          (clock_t)LBOLT_WAITFREE64
 103
 104 /*
 105  * LBOLT_FASTPATH{,64} should *only* be used where the cost of calling the
 106  * DDI lbolt routines affects performance. This is currently only used by
 107  * the TCP/IP code and will be removed once it's no longer required.
 108  */
 109 #define LBOLT_FASTPATH64                                                \
 110         (lbolt_hybrid == lbolt_cyclic_driven ?                          \
 111             (lb_info->lbi_internal - lb_info->lbi_debug_time) :         \
 112             lbolt_event_driven())
 113
 114 #define LBOLT_FASTPATH          (clock_t)LBOLT_FASTPATH64
 115
 116 /*
 117  * LBOLT_NO_ACCOUNT{,64} is used by lbolt consumers who fire at a periodic
 118  * rate, such as clock(), for which the lbolt usage statistics are not updated.
 119  * This is especially important for consumers whose rate may be modified by
 120  * the user, resulting in an unaccounted for increase in activity around the
 121  * lbolt routines that could cause a mode switch.
 122  */
 123 #define LBOLT_NO_ACCOUNT64                                              \
 124         (lbolt_hybrid == lbolt_bootstrap ? 0 :                          \
 125         (lbolt_hybrid == lbolt_event_driven ?                           \
 126             ((gethrtime()/nsec_per_tick) - lb_info->lbi_debug_time) :   \
 127             (lb_info->lbi_internal - lb_info->lbi_debug_time)))
 128
 129 #define LBOLT_NO_ACCOUNT        (clock_t)LBOLT_NO_ACCOUNT64
 130
 131 #endif  /* _KERNEL || _KMEMUSER */
 132
 133 #ifdef  __cplusplus
 134 }
 135 #endif
 136
 137 #endif /* _SYS_CLOCK_IMPL_H */