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/jiffies.h>
  18 #include <linux/slab.h>
  19 #include <linux/types.h>
  20 #include <linux/interrupt.h>
  21
  22 #include <net/ip_vs.h>
  23
  24 /*
  25   This code is to estimate rate in a shorter interval (such as 8
  26   seconds) for virtual services and real servers. For measure rate in a
  27   long interval, it is easy to implement a user level daemon which
  28   periodically reads those statistical counters and measure rate.
  29
  30   Currently, the measurement is activated by slow timer handler. Hope
  31   this measurement will not introduce too much load.
  32
  33   We measure rate during the last 8 seconds every 2 seconds:
  34
  35     avgrate = avgrate*(1-W) + rate*W
  36
  37     where W = 2^(-2)
  38
  39   NOTES.
  40
  41   * The stored value for average bps is scaled by 2^5, so that maximal
  42     rate is ~2.15Gbits/s, average pps and cps are scaled by 2^10.
  43
  44   * A lot code is taken from net/sched/estimator.c
  45  */
  46
  47
  48 struct ip_vs_estimator
  49 {
  50         struct ip_vs_estimator  *next;
  51         struct ip_vs_stats      *stats;
  52
  53         u32                     last_conns;
  54         u32                     last_inpkts;
  55         u32                     last_outpkts;
  56         u64                     last_inbytes;
  57         u64                     last_outbytes;
  58
  59         u32                     cps;
  60         u32                     inpps;
  61         u32                     outpps;
  62         u32                     inbps;
  63         u32                     outbps;
  64 };
  65
  66
  67 static struct ip_vs_estimator *est_list = NULL;
  68 static DEFINE_RWLOCK(est_lock);
  69 static struct timer_list est_timer;
  70
  71 static void estimation_timer(unsigned long arg)
  72 {
  73         struct ip_vs_estimator *e;
  74         struct ip_vs_stats *s;
  75         u32 n_conns;
  76         u32 n_inpkts, n_outpkts;
  77         u64 n_inbytes, n_outbytes;
  78         u32 rate;
  79
  80         read_lock(&est_lock);
  81         for (e = est_list; e; e = e->next) {
  82                 s = e->stats;
  83
  84                 spin_lock(&s->lock);
  85                 n_conns = s->conns;
  86                 n_inpkts = s->inpkts;
  87                 n_outpkts = s->outpkts;
  88                 n_inbytes = s->inbytes;
  89                 n_outbytes = s->outbytes;
  90
  91                 /* scaled by 2^10, but divided 2 seconds */
  92                 rate = (n_conns - e->last_conns)<<9;
  93                 e->last_conns = n_conns;
  94                 e->cps += ((long)rate - (long)e->cps)>>2;
  95                 s->cps = (e->cps+0x1FF)>>10;
  96
  97                 rate = (n_inpkts - e->last_inpkts)<<9;
  98                 e->last_inpkts = n_inpkts;
  99                 e->inpps += ((long)rate - (long)e->inpps)>>2;
 100                 s->inpps = (e->inpps+0x1FF)>>10;
 101
 102                 rate = (n_outpkts - e->last_outpkts)<<9;
 103                 e->last_outpkts = n_outpkts;
 104                 e->outpps += ((long)rate - (long)e->outpps)>>2;
 105                 s->outpps = (e->outpps+0x1FF)>>10;
 106
 107                 rate = (n_inbytes - e->last_inbytes)<<4;
 108                 e->last_inbytes = n_inbytes;
 109                 e->inbps += ((long)rate - (long)e->inbps)>>2;
 110                 s->inbps = (e->inbps+0xF)>>5;
 111
 112                 rate = (n_outbytes - e->last_outbytes)<<4;
 113                 e->last_outbytes = n_outbytes;
 114                 e->outbps += ((long)rate - (long)e->outbps)>>2;
 115                 s->outbps = (e->outbps+0xF)>>5;
 116                 spin_unlock(&s->lock);
 117         }
 118         read_unlock(&est_lock);
 119         mod_timer(&est_timer, jiffies + 2*HZ);
 120 }
 121
 122 int ip_vs_new_estimator(struct ip_vs_stats *stats)
 123 {
 124         struct ip_vs_estimator *est;
 125
 126         est = kzalloc(sizeof(*est), GFP_KERNEL);
 127         if (est == NULL)
 128                 return -ENOMEM;
 129
 130         est->stats = stats;
 131         est->last_conns = stats->conns;
 132         est->cps = stats->cps<<10;
 133
 134         est->last_inpkts = stats->inpkts;
 135         est->inpps = stats->inpps<<10;
 136
 137         est->last_outpkts = stats->outpkts;
 138         est->outpps = stats->outpps<<10;
 139
 140         est->last_inbytes = stats->inbytes;
 141         est->inbps = stats->inbps<<5;
 142
 143         est->last_outbytes = stats->outbytes;
 144         est->outbps = stats->outbps<<5;
 145
 146         write_lock_bh(&est_lock);
 147         est->next = est_list;
 148         if (est->next == NULL) {
 149                 init_timer(&est_timer);
 150                 est_timer.expires = jiffies + 2*HZ;
 151                 est_timer.function = estimation_timer;
 152                 add_timer(&est_timer);
 153         }
 154         est_list = est;
 155         write_unlock_bh(&est_lock);
 156         return 0;
 157 }
 158
 159 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 160 {
 161         struct ip_vs_estimator *est, **pest;
 162         int killed = 0;
 163
 164         write_lock_bh(&est_lock);
 165         pest = &est_list;
 166         while ((est=*pest) != NULL) {
 167                 if (est->stats != stats) {
 168                         pest = &est->next;
 169                         continue;
 170                 }
 171                 *pest = est->next;
 172                 kfree(est);
 173                 killed++;
 174         }
 175         if (killed && est_list == NULL)
 176                 del_timer_sync(&est_timer);
 177         write_unlock_bh(&est_lock);
 178 }
 179
 180 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 181 {
 182         struct ip_vs_estimator *e;
 183
 184         write_lock_bh(&est_lock);
 185         for (e = est_list; e; e = e->next) {
 186                 if (e->stats != stats)
 187                         continue;
 188
 189                 /* set counters zero */
 190                 e->last_conns = 0;
 191                 e->last_inpkts = 0;
 192                 e->last_outpkts = 0;
 193                 e->last_inbytes = 0;
 194                 e->last_outbytes = 0;
 195                 e->cps = 0;
 196                 e->inpps = 0;
 197                 e->outpps = 0;
 198                 e->inbps = 0;
 199                 e->outbps = 0;
 200         }
 201         write_unlock_bh(&est_lock);
 202 }