timer_funcs.h

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/*
 * $Id: timer_funcs.h,v 1.2 2006/02/14 18:04:17 andrei Exp $
 *
 *
 * timer related functions (internal)
 *
 * Copyright (C) 2005 iptelorg GmbH
 *
 * This file is part of ser, a free SIP server.
 *
 * ser is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * For a license to use the ser software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact iptel.org by e-mail at the following addresses:
 *    info@iptel.org
 *
 * ser 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/* History:
 * --------
 *  2005-07-27  complete re-design/re-implemnetation (andrei)
 */


#ifndef timer_funcs_h
#define timer_funcs_h

#include "timer.h"


struct timer_head{
        struct timer_ln* volatile next;
        struct timer_ln* volatile prev;
};



/* hierarchical timing wheel with 3 levels
 * Most timeouts should go in the first "wheel" (h0)
 * h0 will contain timers expiring from crt. time up to
 * crt. time + (1<<H0_BITS)/TICKS_HZ s and will use
 * (1<<H0_BITS)*sizeof(struct timer_head) bytes of memory, so arrange it
 * accordingly
 */

#define H0_BITS 14
#define H1_BITS  9 
#define H2_BITS  (32-H1_BITS-H0_BITS)
/* Uses ~280K on a 64 bits system and ~140K on a 32 bit system; for TICKS_HZ=10
 * holds ~ 30 min in the first hash/wheel and ~233h in the first two.
 * More perfomant arrangement: 16, 8, 8 (but eats 1 MB on a 64 bit system, and
 *  512K on a 32 bit one). For TICKS_HZ=10 it holds almost 2h in the
 *  first hash/wheel and ~460h in the first two.
 */

#define H0_ENTRIES (1<<H0_BITS)
#define H1_ENTRIES (1<<H1_BITS)
#define H2_ENTRIES (1<<H2_BITS)

#define H0_MASK (H0_ENTRIES-1)
#define H1_MASK (H1_ENTRIES-1)
#define H1_H0_MASK ((1<<(H0_BITS+H1_BITS))-1)


struct timer_lists{
        struct timer_head  h0[H0_ENTRIES];
        struct timer_head  h1[H1_ENTRIES];
        struct timer_head  h2[H2_ENTRIES];
        struct timer_head  expired; /* list of expired entries */
};

extern struct timer_lists* timer_lst;


#define _timer_init_list(head)  clist_init((head), next, prev)


#define _timer_add_list(head, tl) \
        clist_append((head), (tl), next, prev)

#define _timer_rm_list(tl) \
        clist_rm((tl), next, prev)

#define timer_foreach(tl, head) clist_foreach((head), (tl), next)
#define timer_foreach_safe(tl, tmp, head)       \
        clist_foreach_safe((head), (tl), (tmp), next)




/* generic add timer entry to the timer lists function (see _timer_add)
 * tl->expire must be set previously, delta is the difference in ticks
 * from current time to the timer desired expire (should be tl->expire-*tick)
 * If you don't know delta, you probably want to call _timer_add instead.
 */
static inline int _timer_dist_tl(struct timer_ln* tl, ticks_t delta)
{
        if (delta<H0_ENTRIES){
                if (delta==0){
                        LOG(L_WARN, "WARNING: timer: add_timeout: 0 expire timer added\n");
                        _timer_add_list(&timer_lst->expired, tl);
                }else{
                        _timer_add_list( &timer_lst->h0[tl->expire & H0_MASK], tl);
                }
        }else if (delta<(H0_ENTRIES*H1_ENTRIES)){
                _timer_add_list(&timer_lst->h1[(tl->expire & H1_H0_MASK)>>H0_BITS],tl);
        }else{
                _timer_add_list(&timer_lst->h2[tl->expire>>(H1_BITS+H0_BITS)], tl);
        }
        return 0;
}



#define _timer_mv_expire(h) \
        do{ \
                if ((h)->next!=(struct timer_ln*)(h)){ \
                        clist_append_sublist(&timer_lst->expired, (h)->next, \
                                                                        (h)->prev, next, prev); \
                        _timer_init_list(h); \
                } \
        }while(0)


#if 1

static inline void timer_redist(ticks_t t, struct timer_head *h)
{
        struct timer_ln* tl;
        struct timer_ln* tmp;
        
        timer_foreach_safe(tl, tmp, h){
                _timer_dist_tl(tl, tl->expire-t);
        }
        /* clear the current list */
        _timer_init_list(h);
}

static inline void timer_run(ticks_t t)
{
        /* trust the compiler for optimizing */
        if ((t & H0_MASK)==0){              /*r1*/
                if ((t & H1_H0_MASK)==0){        /*r2*/
                        timer_redist(t, &timer_lst->h2[t>>(H0_BITS+H1_BITS)]);
                }
                
                timer_redist(t, &timer_lst->h1[(t & H1_H0_MASK)>>H0_BITS]);/*r2 >> H0*/
        }
        /*
        DBG("timer_run: ticks %u, expire h0[%u]\n",
                                                (unsigned ) t, (unsigned)(t & H0_MASK));*/
        _timer_mv_expire(&timer_lst->h0[t & H0_MASK]);  /*r1*/
}
#else

static inline void timer_lst_mv0(ticks_t t, struct timer_head* h)
{
        struct timer_ln* tl;
        struct timer_ln* tmp;
        
        timer_foreach_safe(tl, tmp, h){
                        _timer_dist_tl(tl, &timer_lst->h0[tl->expire & H0_MASK]);
        }
        /* clear the current list */
        _timer_init_list(h);
}

static inline void timer_lst_mv1(ticks_t t, struct timer_head* h)
{
        struct timer_ln* tl;
        struct timer_ln* tmp;
        
        timer_foreach_safe(tl, tmp, h){
                if ((tl->expire & H0_MASK)==0) /* directly to h0 */
                        _timer_add_list(tl, &timer_lst->h0[tl->expire & H0_MASK]);
                else  /* to h1 */
                        _timer_add_list(tl, 
                                                &timer_lst->h1[(tl->expire & H1_H0_MASK)>>H0_BITS]);
        }
        /* clear the current list */
        _timer_init_list(h);
}


/* possible faster version */
static inline void timer_run(ticks_t t)
{
        /* trust the compiler for optimizing */
        if ((t & H0_MASK)==0){              /*r1*/
                if ((t & H1_H0_MASK)==0)        /*r2*/
                        /* just move the list "down" to hash1 */
                        timer_lst_mv1(&timer_lst->h2[t>>(H0_BITS+H1_BITS)]); 
                /* move "down" to hash0 */
                timer_lst_mv0(&timer_lst->h1[(t & H1_H0_MASK)>>H0_BITS]);
        }
        _timer_mv_expire(t, &timer_lst->h0[t & H0_MASK]);  /*r1*/
}
#endif



#endif

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