DPDK: Data Plane Development Kit

18.02.0-rc0
rte_timer.h File Reference
#include <stdio.h>
#include <stdint.h>
#include <stddef.h>
#include <rte_common.h>

Go to the source code of this file.

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 *)

Enumerations

enum  rte_timer_type

Functions

void rte_timer_subsystem_init (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)
void rte_timer_manage (void)
void rte_timer_dump_stats (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 75 of file rte_timer.h.

#define RTE_TIMER_PENDING   1

State: timer is scheduled.

Definition at line 76 of file rte_timer.h.

#define RTE_TIMER_RUNNING   2

State: timer function is running.

Definition at line 77 of file rte_timer.h.

#define RTE_TIMER_CONFIG   3

State: timer is being configured.

Definition at line 78 of file rte_timer.h.

#define RTE_TIMER_NO_OWNER   -2

Timer has no owner.

Definition at line 80 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 154 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 120 of file rte_timer.h.

Enumeration Type Documentation

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

Definition at line 85 of file rte_timer.h.

Function Documentation

void rte_timer_subsystem_init ( void  )

Initialize the timer library.

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

Examples:
examples/l2fwd-jobstats/main.c, examples/l2fwd-keepalive/main.c, examples/l3fwd-power/main.c, examples/performance-thread/pthread_shim/main.c, and examples/timer/main.c.
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
timThe timer to initialize.
Examples:
examples/l2fwd-jobstats/main.c, examples/l2fwd-keepalive/main.c, examples/l3fwd-power/main.c, and examples/timer/main.c.
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
timThe timer handle.
ticksThe number of cycles (see rte_get_hpet_hz()) before the callback function is called.
typeThe 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_lcoreThe 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).
fctThe callback function of the timer.
argThe user argument of the callback function.
Returns
  • 0: Success; the timer is scheduled.
  • (-1): Timer is in the RUNNING or CONFIG state.
Examples:
examples/l2fwd-jobstats/main.c, examples/l2fwd-keepalive/main.c, examples/l3fwd-power/main.c, and examples/timer/main.c.
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
timThe timer handle.
ticksThe number of cycles (see rte_get_hpet_hz()) before the callback function is called.
typeThe 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_lcoreThe 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).
fctThe callback function of the timer.
argThe user argument of the callback function.
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
timThe timer handle.
Returns
  • 0: Success; the timer is stopped.
  • (-1): The timer is in the RUNNING or CONFIG state.
Examples:
examples/performance-thread/common/lthread_sched.c, and examples/timer/main.c.
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
timThe timer handle.
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
timThe timer handle.
Returns
  • 0: The timer is not pending.
  • 1: The timer is pending.
void 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.

Examples:
examples/l2fwd-jobstats/main.c, examples/l2fwd-keepalive/main.c, examples/l3fwd-power/main.c, examples/performance-thread/common/lthread_sched.c, and examples/timer/main.c.
void rte_timer_dump_stats ( FILE *  f)

Dump statistics about timers.

Parameters
fA pointer to a file for output