Lines Matching refs:timer
22 #include <gpxe/timer.h>
32 * A retry timer is a binary exponential backoff timer. It can be
35 * This implementation of the timer is designed to satisfy RFC 2988
36 * and therefore be usable as a TCP retransmission timer.
51 * Start timer
53 * @v timer Retry timer
55 * This starts the timer running with the current timeout value. If
56 * stop_timer() is not called before the timer expires, the timer will
57 * be stopped and the timer's callback function will be called.
59 void start_timer ( struct retry_timer *timer ) {
60 if ( ! timer->running )
61 list_add ( &timer->list, &timers );
62 timer->start = currticks();
63 timer->running = 1;
66 if ( timer->min_timeout == 0 )
67 timer->min_timeout = DEFAULT_MIN_TIMEOUT;
69 if ( timer->min_timeout < MIN_TIMEOUT )
70 timer->min_timeout = MIN_TIMEOUT;
72 if ( timer->timeout < timer->min_timeout )
73 timer->timeout = timer->min_timeout;
75 DBG2 ( "Timer %p started at time %ld (expires at %ld)\n",
76 timer, timer->start, ( timer->start + timer->timeout ) );
80 * Start timer with a specified fixed timeout
82 * @v timer Retry timer
85 void start_timer_fixed ( struct retry_timer *timer, unsigned long timeout ) {
86 start_timer ( timer );
87 timer->timeout = timeout;
88 DBG2 ( "Timer %p expiry time changed to %ld\n",
89 timer, ( timer->start + timer->timeout ) );
93 * Stop timer
95 * @v timer Retry timer
97 * This stops the timer and updates the timer's timeout value.
99 void stop_timer ( struct retry_timer *timer ) {
100 unsigned long old_timeout = timer->timeout;
104 /* If timer was already stopped, do nothing */
105 if ( ! timer->running )
108 list_del ( &timer->list );
109 runtime = ( now - timer->start );
110 timer->running = 0;
111 DBG2 ( "Timer %p stopped at time %ld (ran for %ld)\n",
112 timer, now, runtime );
114 /* Update timer. Variables are:
117 * t = timeout value (i.e. timer->timeout)
129 if ( timer->count ) {
130 timer->count--;
132 timer->timeout -= ( timer->timeout >> 3 );
133 timer->timeout += ( runtime >> 1 );
134 if ( timer->timeout != old_timeout ) {
135 DBG ( "Timer %p timeout updated to %ld\n",
136 timer, timer->timeout );
142 * Handle expired timer
144 * @v timer Retry timer
146 static void timer_expired ( struct retry_timer *timer ) {
149 /* Stop timer without performing RTT calculations */
150 DBG2 ( "Timer %p stopped at time %ld on expiry\n",
151 timer, currticks() );
152 assert ( timer->running );
153 list_del ( &timer->list );
154 timer->running = 0;
155 timer->count++;
158 timer->timeout <<= 1;
159 if ( timer->max_timeout == 0 ) /* 0 means "use default timeout" */
160 timer->max_timeout = DEFAULT_MAX_TIMEOUT;
161 if ( ( fail = ( timer->timeout > timer->max_timeout ) ) )
162 timer->timeout = timer->max_timeout;
163 DBG ( "Timer %p timeout backed off to %ld\n",
164 timer, timer->timeout );
167 timer->expired ( timer, fail );
171 * Single-step the retry timer list
173 * @v process Retry timer process
176 struct retry_timer *timer;
181 list_for_each_entry_safe ( timer, tmp, &timers, list ) {
182 used = ( now - timer->start );
183 if ( used >= timer->timeout )
184 timer_expired ( timer );
188 /** Retry timer process */
