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/* vim:ts=8:sts=8:sw=4:noai:noexpandtab
*
* PGM timer thread.
*
* Copyright (c) 2006-2010 Miru Limited.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <impl/i18n.h>
#include <impl/framework.h>
#include <impl/timer.h>
#include <impl/receiver.h>
#include <impl/source.h>
//#define TIMER_DEBUG
/* determine which timer fires next: spm (ihb_tmr), nak_rb_ivl, nak_rpt_ivl, or nak_rdata_ivl
* and check whether its already due.
*
* called in sock creation so locks unrequired.
*/
bool
pgm_timer_prepare (
pgm_sock_t* const sock
)
{
int32_t msec;
/* pre-conditions */
pgm_assert (NULL != sock);
pgm_assert (sock->can_send_data || sock->can_recv_data);
pgm_time_t now = pgm_time_update_now();
pgm_time_t expiration;
if (sock->can_send_data)
expiration = sock->next_ambient_spm;
else
expiration = now + sock->peer_expiry;
sock->next_poll = expiration;
/* advance time again to adjust for processing time out of the event loop, this
* could cause further timers to expire even before checking for new wire data.
*/
msec = pgm_to_msecs ((int64_t)expiration - (int64_t)now);
if (msec < 0)
msec = 0;
else
msec = MIN (INT32_MAX, msec);
pgm_trace (PGM_LOG_ROLE_NETWORK,_("Next expiration in %" PRIi32 "ms"), msec);
return (msec == 0);
}
bool
pgm_timer_check (
pgm_sock_t* const sock
)
{
const pgm_time_t now = pgm_time_update_now();
bool expired;
/* pre-conditions */
pgm_assert (NULL != sock);
pgm_timer_lock (sock);
expired = pgm_time_after_eq (now, sock->next_poll);
pgm_timer_unlock (sock);
return expired;
}
/* return next timer expiration in microseconds (μs)
*/
pgm_time_t
pgm_timer_expiration (
pgm_sock_t* const sock
)
{
const pgm_time_t now = pgm_time_update_now();
pgm_time_t expiration;
/* pre-conditions */
pgm_assert (NULL != sock);
pgm_timer_lock (sock);
expiration = pgm_time_after (sock->next_poll, now) ? pgm_to_usecs (sock->next_poll - now) : 0;
pgm_timer_unlock (sock);
return expiration;
}
/* call all timers, assume that time_now has been updated by either pgm_timer_prepare
* or pgm_timer_check and no other method calls here.
*
* returns TRUE on success, returns FALSE on blocked send-in-receive operation.
*/
bool
pgm_timer_dispatch (
pgm_sock_t* const sock
)
{
const pgm_time_t now = pgm_time_update_now();
pgm_time_t next_expiration = 0;
/* pre-conditions */
pgm_assert (NULL != sock);
pgm_debug ("pgm_timer_dispatch (sock:%p)", (const void*)sock);
/* find which timers have expired and call each */
if (sock->can_recv_data)
{
if (!pgm_check_peer_state (sock, now))
return FALSE;
next_expiration = pgm_min_receiver_expiry (now + sock->peer_expiry, sock);
}
if (sock->can_send_data)
{
/* reset congestion control on ACK timeout */
if (sock->use_pgmcc &&
sock->tokens < pgm_fp8 (1) &&
0 != sock->ack_expiry)
{
if (pgm_time_after_eq (now, sock->ack_expiry))
{
#ifdef DEBUG_PGMCC
char nows[1024];
time_t t = time (NULL);
struct tm* tmp = localtime (&t);
strftime (nows, sizeof(nows), "%Y-%m-%d %H:%M:%S", tmp);
printf ("ACK timeout, T:%u W:%u\n", pgm_fp8tou(sock->tokens), pgm_fp8tou(sock->cwnd_size));
#endif
sock->tokens = sock->cwnd_size = pgm_fp8 (1);
sock->ack_bitmap = 0xffffffff;
sock->ack_expiry = 0;
/* notify blocking tx thread that transmission time is now available */
pgm_notify_send (&sock->ack_notify);
}
next_expiration = next_expiration > 0 ? MIN(next_expiration, sock->ack_expiry) : sock->ack_expiry;
}
/* SPM broadcast */
pgm_mutex_lock (&sock->timer_mutex);
const unsigned spm_heartbeat_state = sock->spm_heartbeat_state;
const pgm_time_t next_heartbeat_spm = sock->next_heartbeat_spm;
pgm_mutex_unlock (&sock->timer_mutex);
/* no lock needed on ambient */
const pgm_time_t next_ambient_spm = sock->next_ambient_spm;
pgm_time_t next_spm = spm_heartbeat_state ? MIN(next_heartbeat_spm, next_ambient_spm) : next_ambient_spm;
if (pgm_time_after_eq (now, next_spm) &&
!pgm_send_spm (sock, 0))
return FALSE;
/* ambient timing not so important so base next event off current time */
if (pgm_time_after_eq (now, next_ambient_spm))
{
sock->next_ambient_spm = now + sock->spm_ambient_interval;
next_spm = spm_heartbeat_state ? MIN(next_heartbeat_spm, sock->next_ambient_spm) : sock->next_ambient_spm;
}
/* heartbeat timing is often high resolution so base times to last event */
if (spm_heartbeat_state && pgm_time_after_eq (now, next_heartbeat_spm))
{
unsigned new_heartbeat_state = spm_heartbeat_state;
pgm_time_t new_heartbeat_spm = next_heartbeat_spm;
do {
new_heartbeat_spm += sock->spm_heartbeat_interval[new_heartbeat_state++];
if (new_heartbeat_state == sock->spm_heartbeat_len) {
new_heartbeat_state = 0;
new_heartbeat_spm = now + sock->spm_ambient_interval;
break;
}
} while (pgm_time_after_eq (now, new_heartbeat_spm));
/* check for reset heartbeat */
pgm_mutex_lock (&sock->timer_mutex);
if (next_heartbeat_spm == sock->next_heartbeat_spm) {
sock->spm_heartbeat_state = new_heartbeat_state;
sock->next_heartbeat_spm = new_heartbeat_spm;
next_spm = MIN(sock->next_ambient_spm, new_heartbeat_spm);
} else
next_spm = MIN(sock->next_ambient_spm, sock->next_heartbeat_spm);
sock->next_poll = next_expiration > 0 ? MIN(next_expiration, next_spm) : next_spm;
pgm_mutex_unlock (&sock->timer_mutex);
return TRUE;
}
next_expiration = next_expiration > 0 ? MIN(next_expiration, next_spm) : next_spm;
/* check for reset */
pgm_mutex_lock (&sock->timer_mutex);
sock->next_poll = sock->next_poll > now ? MIN(sock->next_poll, next_expiration) : next_expiration;
pgm_mutex_unlock (&sock->timer_mutex);
}
else
sock->next_poll = next_expiration;
return TRUE;
}
/* eof */
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