net/ipv4/ipvs/ip_vs_est.c

   1 /*
   2  * ip_vs_est.c: simple rate estimator for IPVS
   3  *
   4  * Version:     $Id: ip_vs_est.c,v 1.4 2002/11/30 01:50:35 wensong Exp $
   5  *
   6  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   7  *
   8  *              This program is free software; you can redistribute it and/or
   9  *              modify it under the terms of the GNU General Public License
  10  *              as published by the Free Software Foundation; either version
  11  *              2 of the License, or (at your option) any later version.
  12  *
  13  * Changes:
  14  *
  15  */
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18
  19 #include <net/ip_vs.h>
  20
  21 /*
  22   This code is to estimate rate in a shorter interval (such as 8
  23   seconds) for virtual services and real servers. For measure rate in a
  24   long interval, it is easy to implement a user level daemon which
  25   periodically reads those statistical counters and measure rate.
  26
  27   Currently, the measurement is activated by slow timer handler. Hope
  28   this measurement will not introduce too much load.
  29
  30   We measure rate during the last 8 seconds every 2 seconds:
  31
  32     avgrate = avgrate*(1-W) + rate*W
  33
  34     where W = 2^(-2)
  35
  36   NOTES.
  37
  38   * The stored value for average bps is scaled by 2^5, so that maximal
  39     rate is ~2.15Gbits/s, average pps and cps are scaled by 2^10.
  40
  41   * A lot code is taken from net/sched/estimator.c
  42  */
  43
  44
  45 struct ip_vs_estimator
  46 {
  47         struct ip_vs_estimator  *next;
  48         struct ip_vs_stats      *stats;
  49
  50         u32                     last_conns;
  51         u32                     last_inpkts;
  52         u32                     last_outpkts;
  53         u64                     last_inbytes;
  54         u64                     last_outbytes;
  55
  56         u32                     cps;
  57         u32                     inpps;
  58         u32                     outpps;
  59         u32                     inbps;
  60         u32                     outbps;
  61 };
  62
  63
  64 static struct ip_vs_estimator *est_list = NULL;
  65 static DEFINE_RWLOCK(est_lock);
  66 static struct timer_list est_timer;
  67
  68 static void estimation_timer(unsigned long arg)
  69 {
  70         struct ip_vs_estimator *e;
  71         struct ip_vs_stats *s;
  72         u32 n_conns;
  73         u32 n_inpkts, n_outpkts;
  74         u64 n_inbytes, n_outbytes;
  75         u32 rate;
  76
  77         read_lock(&est_lock);
  78         for (e = est_list; e; e = e->next) {
  79                 s = e->stats;
  80
  81                 spin_lock(&s->lock);
  82                 n_conns = s->conns;
  83                 n_inpkts = s->inpkts;
  84                 n_outpkts = s->outpkts;
  85                 n_inbytes = s->inbytes;
  86                 n_outbytes = s->outbytes;
  87
  88                 /* scaled by 2^10, but divided 2 seconds */
  89                 rate = (n_conns - e->last_conns)<<9;
  90                 e->last_conns = n_conns;
  91                 e->cps += ((long)rate - (long)e->cps)>>2;
  92                 s->cps = (e->cps+0x1FF)>>10;
  93
  94                 rate = (n_inpkts - e->last_inpkts)<<9;
  95                 e->last_inpkts = n_inpkts;
  96                 e->inpps += ((long)rate - (long)e->inpps)>>2;
  97                 s->inpps = (e->inpps+0x1FF)>>10;
  98
  99                 rate = (n_outpkts - e->last_outpkts)<<9;
 100                 e->last_outpkts = n_outpkts;
 101                 e->outpps += ((long)rate - (long)e->outpps)>>2;
 102                 s->outpps = (e->outpps+0x1FF)>>10;
 103
 104                 rate = (n_inbytes - e->last_inbytes)<<4;
 105                 e->last_inbytes = n_inbytes;
 106                 e->inbps += ((long)rate - (long)e->inbps)>>2;
 107                 s->inbps = (e->inbps+0xF)>>5;
 108
 109                 rate = (n_outbytes - e->last_outbytes)<<4;
 110                 e->last_outbytes = n_outbytes;
 111                 e->outbps += ((long)rate - (long)e->outbps)>>2;
 112                 s->outbps = (e->outbps+0xF)>>5;
 113                 spin_unlock(&s->lock);
 114         }
 115         read_unlock(&est_lock);
 116         mod_timer(&est_timer, jiffies + 2*HZ);
 117 }
 118
 119 int ip_vs_new_estimator(struct ip_vs_stats *stats)
 120 {
 121         struct ip_vs_estimator *est;
 122
 123         est = kmalloc(sizeof(*est), GFP_KERNEL);
 124         if (est == NULL)
 125                 return -ENOMEM;
 126
 127         memset(est, 0, sizeof(*est));
 128         est->stats = stats;
 129         est->last_conns = stats->conns;
 130         est->cps = stats->cps<<10;
 131
 132         est->last_inpkts = stats->inpkts;
 133         est->inpps = stats->inpps<<10;
 134
 135         est->last_outpkts = stats->outpkts;
 136         est->outpps = stats->outpps<<10;
 137
 138         est->last_inbytes = stats->inbytes;
 139         est->inbps = stats->inbps<<5;
 140
 141         est->last_outbytes = stats->outbytes;
 142         est->outbps = stats->outbps<<5;
 143
 144         write_lock_bh(&est_lock);
 145         est->next = est_list;
 146         if (est->next == NULL) {
 147                 init_timer(&est_timer);
 148                 est_timer.expires = jiffies + 2*HZ;
 149                 est_timer.function = estimation_timer;
 150                 add_timer(&est_timer);
 151         }
 152         est_list = est;
 153         write_unlock_bh(&est_lock);
 154         return 0;
 155 }
 156
 157 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 158 {
 159         struct ip_vs_estimator *est, **pest;
 160         int killed = 0;
 161
 162         write_lock_bh(&est_lock);
 163         pest = &est_list;
 164         while ((est=*pest) != NULL) {
 165                 if (est->stats != stats) {
 166                         pest = &est->next;
 167                         continue;
 168                 }
 169                 *pest = est->next;
 170                 kfree(est);
 171                 killed++;
 172         }
 173         if (killed && est_list == NULL)
 174                 del_timer_sync(&est_timer);
 175         write_unlock_bh(&est_lock);
 176 }
 177
 178 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 179 {
 180         struct ip_vs_estimator *e;
 181
 182         write_lock_bh(&est_lock);
 183         for (e = est_list; e; e = e->next) {
 184                 if (e->stats != stats)
 185                         continue;
 186
 187                 /* set counters zero */
 188                 e->last_conns = 0;
 189                 e->last_inpkts = 0;
 190                 e->last_outpkts = 0;
 191                 e->last_inbytes = 0;
 192                 e->last_outbytes = 0;
 193                 e->cps = 0;
 194                 e->inpps = 0;
 195                 e->outpps = 0;
 196                 e->inbps = 0;
 197                 e->outbps = 0;
 198         }
 199         write_unlock_bh(&est_lock);
 200 }