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rte_timer.h(3) DPDK rte_timer.h(3)

NAME

rte_timer.h

SYNOPSIS

#include <stdio.h>
#include <stdint.h>
#include <rte_common.h>
#include <rte_spinlock.h>

Data Structures


union rte_timer_status
struct rte_timer

Macros


#define RTE_TIMER_STOP 0
#define RTE_TIMER_PENDING 1
#define RTE_TIMER_RUNNING 2
#define RTE_TIMER_CONFIG 3
#define RTE_TIMER_NO_OWNER -2
#define RTE_TIMER_INITIALIZER

Typedefs


typedef void(* rte_timer_cb_t) (struct rte_timer *, void *)
typedef void(* rte_timer_alt_manage_cb_t) (struct rte_timer *tim)
typedef void(* rte_timer_stop_all_cb_t) (struct rte_timer *tim, void *arg)

Enumerations


enum rte_timer_type

Functions


int rte_timer_data_alloc (uint32_t *id_ptr)
int rte_timer_data_dealloc (uint32_t id)
int rte_timer_subsystem_init (void)
void rte_timer_subsystem_finalize (void)
void rte_timer_init (struct rte_timer *tim)
int rte_timer_reset (struct rte_timer *tim, uint64_t ticks, enum rte_timer_type type, unsigned tim_lcore, rte_timer_cb_t fct, void *arg)
void rte_timer_reset_sync (struct rte_timer *tim, uint64_t ticks, enum rte_timer_type type, unsigned tim_lcore, rte_timer_cb_t fct, void *arg)
int rte_timer_stop (struct rte_timer *tim)
void rte_timer_stop_sync (struct rte_timer *tim)
int rte_timer_pending (struct rte_timer *tim)
int64_t rte_timer_next_ticks (void)
int rte_timer_manage (void)
int rte_timer_dump_stats (FILE *f)
int rte_timer_alt_reset (uint32_t timer_data_id, struct rte_timer *tim, uint64_t ticks, enum rte_timer_type type, unsigned int tim_lcore, rte_timer_cb_t fct, void *arg)
int rte_timer_alt_stop (uint32_t timer_data_id, struct rte_timer *tim)
int rte_timer_alt_manage (uint32_t timer_data_id, unsigned int *poll_lcores, int n_poll_lcores, rte_timer_alt_manage_cb_t f)
int rte_timer_stop_all (uint32_t timer_data_id, unsigned int *walk_lcores, int nb_walk_lcores, rte_timer_stop_all_cb_t f, void *f_arg)
int rte_timer_alt_dump_stats (uint32_t timer_data_id, FILE *f)

Detailed Description

RTE Timer

This library provides a timer service to RTE Data Plane execution units that allows the execution of callback functions asynchronously.

  • Timers can be periodic or single (one-shot).
  • The timers can be loaded from one core and executed on another. This has to be specified in the call to rte_timer_reset().
  • High precision is possible. NOTE: this depends on the call frequency to rte_timer_manage() that check the timer expiration for the local core.
  • If not used in an application, for improved performance, it can be disabled at compilation time by not calling the rte_timer_manage() to improve performance.

The timer library uses the rte_get_hpet_cycles() function that uses the HPET, when available, to provide a reliable time reference. [HPET routines are provided by EAL, which falls back to using the chip TSC (time- stamp counter) as fallback when HPET is not available]

This library provides an interface to add, delete and restart a timer. The API is based on the BSD callout(9) API with a few differences.

See the RTE architecture documentation for more information about the design of this library.

Definition in file rte_timer.h.

Macro Definition Documentation

#define RTE_TIMER_STOP 0

State: timer is stopped.

Definition at line 47 of file rte_timer.h.

#define RTE_TIMER_PENDING 1

State: timer is scheduled.

Definition at line 48 of file rte_timer.h.

#define RTE_TIMER_RUNNING 2

State: timer function is running.

Definition at line 49 of file rte_timer.h.

#define RTE_TIMER_CONFIG 3

State: timer is being configured.

Definition at line 50 of file rte_timer.h.

#define RTE_TIMER_NO_OWNER -2

Timer has no owner.

Definition at line 52 of file rte_timer.h.

#define RTE_TIMER_INITIALIZER

Value:

{                              .status = {{                                     .state = RTE_TIMER_STOP,                 .owner = RTE_TIMER_NO_OWNER,         }},                                      }
A static initializer for a timer structure.

Definition at line 125 of file rte_timer.h.

Typedef Documentation

typedef void(* rte_timer_cb_t) (struct rte_timer *, void *)

Callback function type for timer expiry.

Definition at line 91 of file rte_timer.h.

typedef void(* rte_timer_alt_manage_cb_t) (struct rte_timer *tim)

Callback function type for rte_timer_alt_manage().

Definition at line 436 of file rte_timer.h.

typedef void(* rte_timer_stop_all_cb_t) (struct rte_timer *tim, void *arg)

Callback function type for rte_timer_stop_all().

Definition at line 470 of file rte_timer.h.

Enumeration Type Documentation

enum rte_timer_type

Timer type: Periodic or single (one-shot).

Definition at line 57 of file rte_timer.h.

Function Documentation

int rte_timer_data_alloc (uint32_t * id_ptr)

Allocate a timer data instance in shared memory to track a set of pending timer lists.

Parameters:

id_ptr Pointer to variable into which to write the identifier of the allocated timer data instance.

Returns:

  • 0: Success
  • -ENOSPC: maximum number of timer data instances already allocated

int rte_timer_data_dealloc (uint32_t id)

Deallocate a timer data instance.

Parameters:

id Identifier of the timer data instance to deallocate.

Returns:

  • 0: Success
  • -EINVAL: invalid timer data instance identifier

int rte_timer_subsystem_init (void)

Initialize the timer library.

Initializes internal variables (list, locks and so on) for the RTE timer library.

Note:

This function must be called in every process before using the library.

Returns:

  • 0: Success
  • -ENOMEM: Unable to allocate memory needed to initialize timer subsystem
  • -EALREADY: timer subsystem was already initialized. Not an error.

void rte_timer_subsystem_finalize (void)

Free timer subsystem resources.

void rte_timer_init (struct rte_timer * tim)

Initialize a timer handle.

The rte_timer_init() function initializes the timer handle tim for use. No operations can be performed on a timer before it is initialized.

Parameters:

tim The timer to initialize.

int rte_timer_reset (struct rte_timer * tim, uint64_t ticks, enum rte_timer_type type, unsigned tim_lcore, rte_timer_cb_t fct, void * arg)

Reset and start the timer associated with the timer handle.

The rte_timer_reset() function resets and starts the timer associated with the timer handle tim. When the timer expires after ticks HPET cycles, the function specified by fct will be called with the argument arg on core tim_lcore.

If the timer associated with the timer handle is already running (in the RUNNING state), the function will fail. The user has to check the return value of the function to see if there is a chance that the timer is in the RUNNING state.

If the timer is being configured on another core (the CONFIG state), it will also fail.

If the timer is pending or stopped, it will be rescheduled with the new parameters.

Parameters:

tim The timer handle.
ticks The number of cycles (see rte_get_hpet_hz()) before the callback function is called.
type The type can be either:
  • PERIODICAL: The timer is automatically reloaded after execution (returns to the PENDING state)
  • SINGLE: The timer is one-shot, that is, the timer goes to a STOPPED state after execution.

tim_lcore The ID of the lcore where the timer callback function has to be executed. If tim_lcore is LCORE_ID_ANY, the timer library will launch it on a different core for each call (round-robin).
fct The callback function of the timer.
arg The user argument of the callback function.

Returns:

  • 0: Success; the timer is scheduled.
  • (-1): Timer is in the RUNNING or CONFIG state.

void rte_timer_reset_sync (struct rte_timer * tim, uint64_t ticks, enum rte_timer_type type, unsigned tim_lcore, rte_timer_cb_t fct, void * arg)

Loop until rte_timer_reset() succeeds.

Reset and start the timer associated with the timer handle. Always succeed. See rte_timer_reset() for details.

Parameters:

tim The timer handle.
ticks The number of cycles (see rte_get_hpet_hz()) before the callback function is called.
type The type can be either:
  • PERIODICAL: The timer is automatically reloaded after execution (returns to the PENDING state)
  • SINGLE: The timer is one-shot, that is, the timer goes to a STOPPED state after execution.

tim_lcore The ID of the lcore where the timer callback function has to be executed. If tim_lcore is LCORE_ID_ANY, the timer library will launch it on a different core for each call (round-robin).
fct The callback function of the timer.
arg The user argument of the callback function.

Note:

This API should not be called inside a timer's callback function to reset another timer; doing so could hang in certain scenarios. Instead, the rte_timer_reset() API can be called directly and its return code can be checked for success or failure.

int rte_timer_stop (struct rte_timer * tim)

Stop a timer.

The rte_timer_stop() function stops the timer associated with the timer handle tim. It may fail if the timer is currently running or being configured.

If the timer is pending or stopped (for instance, already expired), the function will succeed. The timer handle tim must have been initialized using rte_timer_init(), otherwise, undefined behavior will occur.

This function can be called safely from a timer callback. If it succeeds, the timer is not referenced anymore by the timer library and the timer structure can be freed (even in the callback function).

Parameters:

tim The timer handle.

Returns:

  • 0: Success; the timer is stopped.
  • (-1): The timer is in the RUNNING or CONFIG state.

void rte_timer_stop_sync (struct rte_timer * tim)

Loop until rte_timer_stop() succeeds.

After a call to this function, the timer identified by tim is stopped. See rte_timer_stop() for details.

Parameters:

tim The timer handle.

Note:

This API should not be called inside a timer's callback function to stop another timer; doing so could hang in certain scenarios. Instead, the rte_timer_stop() API can be called directly and its return code can be checked for success or failure.

int rte_timer_pending (struct rte_timer * tim)

Test if a timer is pending.

The rte_timer_pending() function tests the PENDING status of the timer handle tim. A PENDING timer is one that has been scheduled and whose function has not yet been called.

Parameters:

tim The timer handle.

Returns:

  • 0: The timer is not pending.
  • 1: The timer is pending.

int64_t rte_timer_next_ticks (void)

Time until the next timer on the current lcore This function gives the ticks until the next timer will be active.

Returns:

  • -EINVAL: invalid timer data instance identifier
  • -ENOENT: no timer pending
  • 0: a timer is pending and will run at next rte_timer_manage()
  • >0: ticks until the next timer is ready

int rte_timer_manage (void)

Manage the timer list and execute callback functions.

This function must be called periodically from EAL lcores main_loop(). It browses the list of pending timers and runs all timers that are expired.

The precision of the timer depends on the call frequency of this function. However, the more often the function is called, the more CPU resources it will use.

Returns:

  • 0: Success
  • -EINVAL: timer subsystem not yet initialized

int rte_timer_dump_stats (FILE * f)

Dump statistics about timers.

Parameters:

f A pointer to a file for output

Returns:

  • 0: Success
  • -EINVAL: timer subsystem not yet initialized

int rte_timer_alt_reset (uint32_t timer_data_id, struct rte_timer * tim, uint64_t ticks, enum rte_timer_type type, unsigned int tim_lcore, rte_timer_cb_t fct, void * arg)

This function is the same as rte_timer_reset(), except that it allows a caller to specify the rte_timer_data instance containing the list to which the timer should be added.

See also:

rte_timer_reset()

Parameters:

timer_data_id An identifier indicating which instance of timer data should be used for this operation.
tim The timer handle.
ticks The number of cycles (see rte_get_hpet_hz()) before the callback function is called.
type The type can be either:
  • PERIODICAL: The timer is automatically reloaded after execution (returns to the PENDING state)
  • SINGLE: The timer is one-shot, that is, the timer goes to a STOPPED state after execution.

tim_lcore The ID of the lcore where the timer callback function has to be executed. If tim_lcore is LCORE_ID_ANY, the timer library will launch it on a different core for each call (round-robin).
fct The callback function of the timer. This parameter can be NULL if (and only if) rte_timer_alt_manage() will be used to manage this timer.
arg The user argument of the callback function.

Returns:

  • 0: Success; the timer is scheduled.
  • (-1): Timer is in the RUNNING or CONFIG state.
  • -EINVAL: invalid timer_data_id

int rte_timer_alt_stop (uint32_t timer_data_id, struct rte_timer * tim)

This function is the same as rte_timer_stop(), except that it allows a caller to specify the rte_timer_data instance containing the list from which this timer should be removed.

See also:

rte_timer_stop()

Parameters:

timer_data_id An identifier indicating which instance of timer data should be used for this operation.
tim The timer handle.

Returns:

  • 0: Success; the timer is stopped.
  • (-1): The timer is in the RUNNING or CONFIG state.
  • -EINVAL: invalid timer_data_id

int rte_timer_alt_manage (uint32_t timer_data_id, unsigned int * poll_lcores, int n_poll_lcores, rte_timer_alt_manage_cb_t f)

Manage a set of timer lists and execute the specified callback function for all expired timers. This function is similar to rte_timer_manage(), except that it allows a caller to specify the timer_data instance that should be operated on, as well as a set of lcore IDs identifying which timer lists should be processed. Callback functions of individual timers are ignored.

See also:

rte_timer_manage()

Parameters:

timer_data_id An identifier indicating which instance of timer data should be used for this operation.
poll_lcores An array of lcore ids identifying the timer lists that should be processed. NULL is allowed - if NULL, the timer list corresponding to the lcore calling this routine is processed (same as rte_timer_manage()).
n_poll_lcores The size of the poll_lcores array. If 'poll_lcores' is NULL, this parameter is ignored.
f The callback function which should be called for all expired timers.

Returns:

  • 0: success
  • -EINVAL: invalid timer_data_id

int rte_timer_stop_all (uint32_t timer_data_id, unsigned int * walk_lcores, int nb_walk_lcores, rte_timer_stop_all_cb_t f, void * f_arg)

Walk the pending timer lists for the specified lcore IDs, and for each timer that is encountered, stop it and call the specified callback function to process it further.

Parameters:

timer_data_id An identifier indicating which instance of timer data should be used for this operation.
walk_lcores An array of lcore ids identifying the timer lists that should be processed.
nb_walk_lcores The size of the walk_lcores array.
f The callback function which should be called for each timers. Can be NULL.
f_arg An arbitrary argument that will be passed to f, if it is called.

Returns:

  • 0: success
  • EINVAL: invalid timer_data_id

int rte_timer_alt_dump_stats (uint32_t timer_data_id, FILE * f)

This function is the same as rte_timer_dump_stats(), except that it allows the caller to specify the rte_timer_data instance that should be used.

See also:

rte_timer_dump_stats()

Parameters:

timer_data_id An identifier indicating which instance of timer data should be used for this operation.
f A pointer to a file for output

Returns:

  • 0: success
  • -EINVAL: invalid timer_data_id

Author

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