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41 * This library provides a timer service to RTE Data Plane execution
42 * units that allows the execution of callback functions asynchronously.
44 * - Timers can be periodic or single (one-shot).
45 * - The timers can be loaded from one core and executed on another. This has
46 * to be specified in the call to rte_timer_reset().
47 * - High precision is possible. NOTE: this depends on the call frequency to
48 * rte_timer_manage() that check the timer expiration for the local core.
49 * - If not used in an application, for improved performance, it can be
50 * disabled at compilation time by not calling the rte_timer_manage()
51 * to improve performance.
53 * The timer library uses the rte_get_hpet_cycles() function that
54 * uses the HPET, when available, to provide a reliable time reference. [HPET
55 * routines are provided by EAL, which falls back to using the chip TSC (time-
56 * stamp counter) as fallback when HPET is not available]
58 * This library provides an interface to add, delete and restart a
59 * timer. The API is based on the BSD callout(9) API with a few
62 * See the RTE architecture documentation for more information about the
63 * design of this library.
68 #include <sys/queue.h>
74 #define RTE_TIMER_STOP 0 /**< State: timer is stopped. */
75 #define RTE_TIMER_PENDING 1 /**< State: timer is scheduled. */
76 #define RTE_TIMER_RUNNING 2 /**< State: timer function is running. */
77 #define RTE_TIMER_CONFIG 3 /**< State: timer is being configured. */
79 #define RTE_TIMER_NO_OWNER -1 /**< Timer has no owner. */
82 * Timer type: Periodic or single (one-shot).
90 * Timer status: A union of the state (stopped, pending, running,
91 * config) and an owner (the id of the lcore that owns the timer).
93 union rte_timer_status {
95 uint16_t state; /**< Stop, pending, running, config. */
96 int16_t owner; /**< The lcore that owns the timer. */
98 uint32_t u32; /**< To atomic-set status + owner. */
101 #ifdef RTE_LIBRTE_TIMER_DEBUG
103 * A structure that stores the timer statistics (per-lcore).
105 struct rte_timer_debug_stats {
106 uint64_t reset; /**< Number of success calls to rte_timer_reset(). */
107 uint64_t stop; /**< Number of success calls to rte_timer_stop(). */
108 uint64_t manage; /**< Number of calls to rte_timer_manage(). */
109 uint64_t pending; /**< Number of pending/running timers. */
116 * Callback function type for timer expiry.
118 typedef void (rte_timer_cb_t)(struct rte_timer *, void *);
121 * A structure describing a timer in RTE.
125 LIST_ENTRY(rte_timer) next; /**< Next and prev in list. */
126 volatile union rte_timer_status status; /**< Status of timer. */
127 uint64_t period; /**< Period of timer (0 if not periodic). */
128 uint64_t expire; /**< Time when timer expire. */
129 rte_timer_cb_t *f; /**< Callback function. */
130 void *arg; /**< Argument to callback function. */
136 * A C++ static initializer for a timer structure.
138 #define RTE_TIMER_INITIALIZER { \
140 {{RTE_TIMER_STOP, RTE_TIMER_NO_OWNER}}, \
148 * A static initializer for a timer structure.
150 #define RTE_TIMER_INITIALIZER { \
152 .state = RTE_TIMER_STOP, \
153 .owner = RTE_TIMER_NO_OWNER, \
159 * Initialize the timer library.
161 * Initializes internal variables (list, locks and so on) for the RTE
164 void rte_timer_subsystem_init(void);
167 * Initialize a timer handle.
169 * The rte_timer_init() function initializes the timer handle *tim*
170 * for use. No operations can be performed on a timer before it is
174 * The timer to initialize.
176 void rte_timer_init(struct rte_timer *tim);
179 * Reset and start the timer associated with the timer handle.
181 * The rte_timer_reset() function resets and starts the timer
182 * associated with the timer handle *tim*. When the timer expires after
183 * *ticks* HPET cycles, the function specified by *fct* will be called
184 * with the argument *arg* on core *tim_lcore*.
186 * If the timer associated with the timer handle is already running
187 * (in the RUNNING state), the function will fail. The user has to check
188 * the return value of the function to see if there is a chance that the
189 * timer is in the RUNNING state.
191 * If the timer is being configured on another core (the CONFIG state),
194 * If the timer is pending or stopped, it will be rescheduled with the
200 * The number of cycles (see rte_get_hpet_hz()) before the callback
201 * function is called.
203 * The type can be either:
204 * - PERIODICAL: The timer is automatically reloaded after execution
205 * (returns to the PENDING state)
206 * - SINGLE: The timer is one-shot, that is, the timer goes to a
207 * STOPPED state after execution.
209 * The ID of the lcore where the timer callback function has to be
210 * executed. If tim_lcore is LCORE_ID_ANY, the timer library will
211 * launch it on a different core for each call (round-robin).
213 * The callback function of the timer.
215 * The user argument of the callback function.
217 * - 0: Success; the timer is scheduled.
218 * - (-1): Timer is in the RUNNING or CONFIG state.
220 int rte_timer_reset(struct rte_timer *tim, uint64_t ticks,
221 enum rte_timer_type type, unsigned tim_lcore,
222 rte_timer_cb_t fct, void *arg);
226 * Loop until rte_timer_reset() succeeds.
228 * Reset and start the timer associated with the timer handle. Always
229 * succeed. See rte_timer_reset() for details.
234 * The number of cycles (see rte_get_hpet_hz()) before the callback
235 * function is called.
237 * The type can be either:
238 * - PERIODICAL: The timer is automatically reloaded after execution
239 * (returns to the PENDING state)
240 * - SINGLE: The timer is one-shot, that is, the timer goes to a
241 * STOPPED state after execution.
243 * The ID of the lcore where the timer callback function has to be
244 * executed. If tim_lcore is LCORE_ID_ANY, the timer library will
245 * launch it on a different core for each call (round-robin).
247 * The callback function of the timer.
249 * The user argument of the callback function.
252 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
253 enum rte_timer_type type, unsigned tim_lcore,
254 rte_timer_cb_t fct, void *arg);
259 * The rte_timer_stop() function stops the timer associated with the
260 * timer handle *tim*. It may fail if the timer is currently running or
263 * If the timer is pending or stopped (for instance, already expired),
264 * the function will succeed. The timer handle tim must have been
265 * initialized using rte_timer_init(), otherwise, undefined behavior
268 * This function can be called safely from a timer callback. If it
269 * succeeds, the timer is not referenced anymore by the timer library
270 * and the timer structure can be freed (even in the callback
276 * - 0: Success; the timer is stopped.
277 * - (-1): The timer is in the RUNNING or CONFIG state.
279 int rte_timer_stop(struct rte_timer *tim);
283 * Loop until rte_timer_stop() succeeds.
285 * After a call to this function, the timer identified by *tim* is
286 * stopped. See rte_timer_stop() for details.
291 void rte_timer_stop_sync(struct rte_timer *tim);
294 * Test if a timer is pending.
296 * The rte_timer_pending() function tests the PENDING status
297 * of the timer handle *tim*. A PENDING timer is one that has been
298 * scheduled and whose function has not yet been called.
303 * - 0: The timer is not pending.
304 * - 1: The timer is pending.
306 int rte_timer_pending(struct rte_timer *tim);
309 * Manage the timer list and execute callback functions.
311 * This function must be called periodically from all cores
312 * main_loop(). It browses the list of pending timers and runs all
313 * timers that are expired.
315 * The precision of the timer depends on the call frequency of this
316 * function. However, the more often the function is called, the more
317 * CPU resources it will use.
319 void rte_timer_manage(void);
322 * Dump statistics about timers.
324 void rte_timer_dump_stats(void);
330 #endif /* _RTE_TIMER_H_ */