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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.
69 #include <rte_common.h>
70 #include <rte_config.h>
76 #define RTE_TIMER_STOP 0 /**< State: timer is stopped. */
77 #define RTE_TIMER_PENDING 1 /**< State: timer is scheduled. */
78 #define RTE_TIMER_RUNNING 2 /**< State: timer function is running. */
79 #define RTE_TIMER_CONFIG 3 /**< State: timer is being configured. */
81 #define RTE_TIMER_NO_OWNER -2 /**< Timer has no owner. */
84 * Timer type: Periodic or single (one-shot).
92 * Timer status: A union of the state (stopped, pending, running,
93 * config) and an owner (the id of the lcore that owns the timer).
95 union rte_timer_status {
98 uint16_t state; /**< Stop, pending, running, config. */
99 int16_t owner; /**< The lcore that owns the timer. */
101 uint32_t u32; /**< To atomic-set status + owner. */
104 #ifdef RTE_LIBRTE_TIMER_DEBUG
106 * A structure that stores the timer statistics (per-lcore).
108 struct rte_timer_debug_stats {
109 uint64_t reset; /**< Number of success calls to rte_timer_reset(). */
110 uint64_t stop; /**< Number of success calls to rte_timer_stop(). */
111 uint64_t manage; /**< Number of calls to rte_timer_manage(). */
112 uint64_t pending; /**< Number of pending/running timers. */
119 * Callback function type for timer expiry.
121 typedef void (*rte_timer_cb_t)(struct rte_timer *, void *);
123 #define MAX_SKIPLIST_DEPTH 10
126 * A structure describing a timer in RTE.
130 uint64_t expire; /**< Time when timer expire. */
131 struct rte_timer *sl_next[MAX_SKIPLIST_DEPTH];
132 volatile union rte_timer_status status; /**< Status of timer. */
133 uint64_t period; /**< Period of timer (0 if not periodic). */
134 rte_timer_cb_t f; /**< Callback function. */
135 void *arg; /**< Argument to callback function. */
141 * A C++ static initializer for a timer structure.
143 #define RTE_TIMER_INITIALIZER { \
146 {{RTE_TIMER_STOP, RTE_TIMER_NO_OWNER}}, \
153 * A static initializer for a timer structure.
155 #define RTE_TIMER_INITIALIZER { \
157 .state = RTE_TIMER_STOP, \
158 .owner = RTE_TIMER_NO_OWNER, \
164 * Initialize the timer library.
166 * Initializes internal variables (list, locks and so on) for the RTE
169 void rte_timer_subsystem_init(void);
172 * Initialize a timer handle.
174 * The rte_timer_init() function initializes the timer handle *tim*
175 * for use. No operations can be performed on a timer before it is
179 * The timer to initialize.
181 void rte_timer_init(struct rte_timer *tim);
184 * Reset and start the timer associated with the timer handle.
186 * The rte_timer_reset() function resets and starts the timer
187 * associated with the timer handle *tim*. When the timer expires after
188 * *ticks* HPET cycles, the function specified by *fct* will be called
189 * with the argument *arg* on core *tim_lcore*.
191 * If the timer associated with the timer handle is already running
192 * (in the RUNNING state), the function will fail. The user has to check
193 * the return value of the function to see if there is a chance that the
194 * timer is in the RUNNING state.
196 * If the timer is being configured on another core (the CONFIG state),
199 * If the timer is pending or stopped, it will be rescheduled with the
205 * The number of cycles (see rte_get_hpet_hz()) before the callback
206 * function is called.
208 * The type can be either:
209 * - PERIODICAL: The timer is automatically reloaded after execution
210 * (returns to the PENDING state)
211 * - SINGLE: The timer is one-shot, that is, the timer goes to a
212 * STOPPED state after execution.
214 * The ID of the lcore where the timer callback function has to be
215 * executed. If tim_lcore is LCORE_ID_ANY, the timer library will
216 * launch it on a different core for each call (round-robin).
218 * The callback function of the timer.
220 * The user argument of the callback function.
222 * - 0: Success; the timer is scheduled.
223 * - (-1): Timer is in the RUNNING or CONFIG state.
225 int rte_timer_reset(struct rte_timer *tim, uint64_t ticks,
226 enum rte_timer_type type, unsigned tim_lcore,
227 rte_timer_cb_t fct, void *arg);
231 * Loop until rte_timer_reset() succeeds.
233 * Reset and start the timer associated with the timer handle. Always
234 * succeed. See rte_timer_reset() for details.
239 * The number of cycles (see rte_get_hpet_hz()) before the callback
240 * function is called.
242 * The type can be either:
243 * - PERIODICAL: The timer is automatically reloaded after execution
244 * (returns to the PENDING state)
245 * - SINGLE: The timer is one-shot, that is, the timer goes to a
246 * STOPPED state after execution.
248 * The ID of the lcore where the timer callback function has to be
249 * executed. If tim_lcore is LCORE_ID_ANY, the timer library will
250 * launch it on a different core for each call (round-robin).
252 * The callback function of the timer.
254 * The user argument of the callback function.
257 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
258 enum rte_timer_type type, unsigned tim_lcore,
259 rte_timer_cb_t fct, void *arg);
264 * The rte_timer_stop() function stops the timer associated with the
265 * timer handle *tim*. It may fail if the timer is currently running or
268 * If the timer is pending or stopped (for instance, already expired),
269 * the function will succeed. The timer handle tim must have been
270 * initialized using rte_timer_init(), otherwise, undefined behavior
273 * This function can be called safely from a timer callback. If it
274 * succeeds, the timer is not referenced anymore by the timer library
275 * and the timer structure can be freed (even in the callback
281 * - 0: Success; the timer is stopped.
282 * - (-1): The timer is in the RUNNING or CONFIG state.
284 int rte_timer_stop(struct rte_timer *tim);
288 * Loop until rte_timer_stop() succeeds.
290 * After a call to this function, the timer identified by *tim* is
291 * stopped. See rte_timer_stop() for details.
296 void rte_timer_stop_sync(struct rte_timer *tim);
299 * Test if a timer is pending.
301 * The rte_timer_pending() function tests the PENDING status
302 * of the timer handle *tim*. A PENDING timer is one that has been
303 * scheduled and whose function has not yet been called.
308 * - 0: The timer is not pending.
309 * - 1: The timer is pending.
311 int rte_timer_pending(struct rte_timer *tim);
314 * Manage the timer list and execute callback functions.
316 * This function must be called periodically from EAL lcores
317 * main_loop(). It browses the list of pending timers and runs all
318 * timers that are expired.
320 * The precision of the timer depends on the call frequency of this
321 * function. However, the more often the function is called, the more
322 * CPU resources it will use.
324 void rte_timer_manage(void);
327 * Dump statistics about timers.
330 * A pointer to a file for output
332 void rte_timer_dump_stats(FILE *f);
338 #endif /* _RTE_TIMER_H_ */