ceph/src/spdk/dpdk/lib/librte_timer/rte_timer.h

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #ifndef _RTE_TIMER_H_
   6 #define _RTE_TIMER_H_
   7
   8 /**
   9  * @file
  10  RTE Timer
  11  *
  12  * This library provides a timer service to RTE Data Plane execution
  13  * units that allows the execution of callback functions asynchronously.
  14  *
  15  * - Timers can be periodic or single (one-shot).
  16  * - The timers can be loaded from one core and executed on another. This has
  17  *   to be specified in the call to rte_timer_reset().
  18  * - High precision is possible. NOTE: this depends on the call frequency to
  19  *   rte_timer_manage() that check the timer expiration for the local core.
  20  * - If not used in an application, for improved performance, it can be
  21  *   disabled at compilation time by not calling the rte_timer_manage()
  22  *   to improve performance.
  23  *
  24  * The timer library uses the rte_get_hpet_cycles() function that
  25  * uses the HPET, when available, to provide a reliable time reference. [HPET
  26  * routines are provided by EAL, which falls back to using the chip TSC (time-
  27  * stamp counter) as fallback when HPET is not available]
  28  *
  29  * This library provides an interface to add, delete and restart a
  30  * timer. The API is based on the BSD callout(9) API with a few
  31  * differences.
  32  *
  33  * See the RTE architecture documentation for more information about the
  34  * design of this library.
  35  */
  36
  37 #include <stdio.h>
  38 #include <stdint.h>
  39 #include <stddef.h>
  40 #include <rte_common.h>
  41 #include <rte_config.h>
  42
  43 #ifdef __cplusplus
  44 extern "C" {
  45 #endif
  46
  47 #define RTE_TIMER_STOP    0 /**< State: timer is stopped. */
  48 #define RTE_TIMER_PENDING 1 /**< State: timer is scheduled. */
  49 #define RTE_TIMER_RUNNING 2 /**< State: timer function is running. */
  50 #define RTE_TIMER_CONFIG  3 /**< State: timer is being configured. */
  51
  52 #define RTE_TIMER_NO_OWNER -2 /**< Timer has no owner. */
  53
  54 /**
  55  * Timer type: Periodic or single (one-shot).
  56  */
  57 enum rte_timer_type {
  58         SINGLE,
  59         PERIODICAL
  60 };
  61
  62 /**
  63  * Timer status: A union of the state (stopped, pending, running,
  64  * config) and an owner (the id of the lcore that owns the timer).
  65  */
  66 union rte_timer_status {
  67         RTE_STD_C11
  68         struct {
  69                 uint16_t state;  /**< Stop, pending, running, config. */
  70                 int16_t owner;   /**< The lcore that owns the timer. */
  71         };
  72         uint32_t u32;            /**< To atomic-set status + owner. */
  73 };
  74
  75 #ifdef RTE_LIBRTE_TIMER_DEBUG
  76 /**
  77  * A structure that stores the timer statistics (per-lcore).
  78  */
  79 struct rte_timer_debug_stats {
  80         uint64_t reset;   /**< Number of success calls to rte_timer_reset(). */
  81         uint64_t stop;    /**< Number of success calls to rte_timer_stop(). */
  82         uint64_t manage;  /**< Number of calls to rte_timer_manage(). */
  83         uint64_t pending; /**< Number of pending/running timers. */
  84 };
  85 #endif
  86
  87 struct rte_timer;
  88
  89 /**
  90  * Callback function type for timer expiry.
  91  */
  92 typedef void (*rte_timer_cb_t)(struct rte_timer *, void *);
  93
  94 #define MAX_SKIPLIST_DEPTH 10
  95
  96 /**
  97  * A structure describing a timer in RTE.
  98  */
  99 struct rte_timer
 100 {
 101         uint64_t expire;       /**< Time when timer expire. */
 102         struct rte_timer *sl_next[MAX_SKIPLIST_DEPTH];
 103         volatile union rte_timer_status status; /**< Status of timer. */
 104         uint64_t period;       /**< Period of timer (0 if not periodic). */
 105         rte_timer_cb_t f;      /**< Callback function. */
 106         void *arg;             /**< Argument to callback function. */
 107 };
 108
 109
 110 #ifdef __cplusplus
 111 /**
 112  * A C++ static initializer for a timer structure.
 113  */
 114 #define RTE_TIMER_INITIALIZER {             \
 115         0,                                      \
 116         {NULL},                                 \
 117         {{RTE_TIMER_STOP, RTE_TIMER_NO_OWNER}}, \
 118         0,                                      \
 119         NULL,                                   \
 120         NULL,                                   \
 121         }
 122 #else
 123 /**
 124  * A static initializer for a timer structure.
 125  */
 126 #define RTE_TIMER_INITIALIZER {                      \
 127                 .status = {{                         \
 128                         .state = RTE_TIMER_STOP,     \
 129                         .owner = RTE_TIMER_NO_OWNER, \
 130                 }},                                  \
 131         }
 132 #endif
 133
 134 /**
 135  * Initialize the timer library.
 136  *
 137  * Initializes internal variables (list, locks and so on) for the RTE
 138  * timer library.
 139  */
 140 void rte_timer_subsystem_init(void);
 141
 142 /**
 143  * Initialize a timer handle.
 144  *
 145  * The rte_timer_init() function initializes the timer handle *tim*
 146  * for use. No operations can be performed on a timer before it is
 147  * initialized.
 148  *
 149  * @param tim
 150  *   The timer to initialize.
 151  */
 152 void rte_timer_init(struct rte_timer *tim);
 153
 154 /**
 155  * Reset and start the timer associated with the timer handle.
 156  *
 157  * The rte_timer_reset() function resets and starts the timer
 158  * associated with the timer handle *tim*. When the timer expires after
 159  * *ticks* HPET cycles, the function specified by *fct* will be called
 160  * with the argument *arg* on core *tim_lcore*.
 161  *
 162  * If the timer associated with the timer handle is already running
 163  * (in the RUNNING state), the function will fail. The user has to check
 164  * the return value of the function to see if there is a chance that the
 165  * timer is in the RUNNING state.
 166  *
 167  * If the timer is being configured on another core (the CONFIG state),
 168  * it will also fail.
 169  *
 170  * If the timer is pending or stopped, it will be rescheduled with the
 171  * new parameters.
 172  *
 173  * @param tim
 174  *   The timer handle.
 175  * @param ticks
 176  *   The number of cycles (see rte_get_hpet_hz()) before the callback
 177  *   function is called.
 178  * @param type
 179  *   The type can be either:
 180  *   - PERIODICAL: The timer is automatically reloaded after execution
 181  *     (returns to the PENDING state)
 182  *   - SINGLE: The timer is one-shot, that is, the timer goes to a
 183  *     STOPPED state after execution.
 184  * @param tim_lcore
 185  *   The ID of the lcore where the timer callback function has to be
 186  *   executed. If tim_lcore is LCORE_ID_ANY, the timer library will
 187  *   launch it on a different core for each call (round-robin).
 188  * @param fct
 189  *   The callback function of the timer.
 190  * @param arg
 191  *   The user argument of the callback function.
 192  * @return
 193  *   - 0: Success; the timer is scheduled.
 194  *   - (-1): Timer is in the RUNNING or CONFIG state.
 195  */
 196 int rte_timer_reset(struct rte_timer *tim, uint64_t ticks,
 197                     enum rte_timer_type type, unsigned tim_lcore,
 198                     rte_timer_cb_t fct, void *arg);
 199
 200
 201 /**
 202  * Loop until rte_timer_reset() succeeds.
 203  *
 204  * Reset and start the timer associated with the timer handle. Always
 205  * succeed. See rte_timer_reset() for details.
 206  *
 207  * @param tim
 208  *   The timer handle.
 209  * @param ticks
 210  *   The number of cycles (see rte_get_hpet_hz()) before the callback
 211  *   function is called.
 212  * @param type
 213  *   The type can be either:
 214  *   - PERIODICAL: The timer is automatically reloaded after execution
 215  *     (returns to the PENDING state)
 216  *   - SINGLE: The timer is one-shot, that is, the timer goes to a
 217  *     STOPPED state after execution.
 218  * @param tim_lcore
 219  *   The ID of the lcore where the timer callback function has to be
 220  *   executed. If tim_lcore is LCORE_ID_ANY, the timer library will
 221  *   launch it on a different core for each call (round-robin).
 222  * @param fct
 223  *   The callback function of the timer.
 224  * @param arg
 225  *   The user argument of the callback function.
 226  */
 227 void
 228 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
 229                      enum rte_timer_type type, unsigned tim_lcore,
 230                      rte_timer_cb_t fct, void *arg);
 231
 232 /**
 233  * Stop a timer.
 234  *
 235  * The rte_timer_stop() function stops the timer associated with the
 236  * timer handle *tim*. It may fail if the timer is currently running or
 237  * being configured.
 238  *
 239  * If the timer is pending or stopped (for instance, already expired),
 240  * the function will succeed. The timer handle tim must have been
 241  * initialized using rte_timer_init(), otherwise, undefined behavior
 242  * will occur.
 243  *
 244  * This function can be called safely from a timer callback. If it
 245  * succeeds, the timer is not referenced anymore by the timer library
 246  * and the timer structure can be freed (even in the callback
 247  * function).
 248  *
 249  * @param tim
 250  *   The timer handle.
 251  * @return
 252  *   - 0: Success; the timer is stopped.
 253  *   - (-1): The timer is in the RUNNING or CONFIG state.
 254  */
 255 int rte_timer_stop(struct rte_timer *tim);
 256
 257
 258 /**
 259  * Loop until rte_timer_stop() succeeds.
 260  *
 261  * After a call to this function, the timer identified by *tim* is
 262  * stopped. See rte_timer_stop() for details.
 263  *
 264  * @param tim
 265  *   The timer handle.
 266  */
 267 void rte_timer_stop_sync(struct rte_timer *tim);
 268
 269 /**
 270  * Test if a timer is pending.
 271  *
 272  * The rte_timer_pending() function tests the PENDING status
 273  * of the timer handle *tim*. A PENDING timer is one that has been
 274  * scheduled and whose function has not yet been called.
 275  *
 276  * @param tim
 277  *   The timer handle.
 278  * @return
 279  *   - 0: The timer is not pending.
 280  *   - 1: The timer is pending.
 281  */
 282 int rte_timer_pending(struct rte_timer *tim);
 283
 284 /**
 285  * Manage the timer list and execute callback functions.
 286  *
 287  * This function must be called periodically from EAL lcores
 288  * main_loop(). It browses the list of pending timers and runs all
 289  * timers that are expired.
 290  *
 291  * The precision of the timer depends on the call frequency of this
 292  * function. However, the more often the function is called, the more
 293  * CPU resources it will use.
 294  */
 295 void rte_timer_manage(void);
 296
 297 /**
 298  * Dump statistics about timers.
 299  *
 300  * @param f
 301  *   A pointer to a file for output
 302  */
 303 void rte_timer_dump_stats(FILE *f);
 304
 305 #ifdef __cplusplus
 306 }
 307 #endif
 308
 309 #endif /* _RTE_TIMER_H_ */