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/config.h>
  17 #include <linux/kernel.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/slab.h>
  20 #include <linux/types.h>
  21 #include <linux/interrupt.h>
  22
  23 #include <net/ip_vs.h>
  24
  25 /*
  26   This code is to estimate rate in a shorter interval (such as 8
  27   seconds) for virtual services and real servers. For measure rate in a
  28   long interval, it is easy to implement a user level daemon which
  29   periodically reads those statistical counters and measure rate.
  30
  31   Currently, the measurement is activated by slow timer handler. Hope
  32   this measurement will not introduce too much load.
  33
  34   We measure rate during the last 8 seconds every 2 seconds:
  35
  36     avgrate = avgrate*(1-W) + rate*W
  37
  38     where W = 2^(-2)
  39
  40   NOTES.
  41
  42   * The stored value for average bps is scaled by 2^5, so that maximal
  43     rate is ~2.15Gbits/s, average pps and cps are scaled by 2^10.
  44
  45   * A lot code is taken from net/sched/estimator.c
  46  */
  47
  48
  49 struct ip_vs_estimator
  50 {
  51         struct ip_vs_estimator  *next;
  52         struct ip_vs_stats      *stats;
  53
  54         u32                     last_conns;
  55         u32                     last_inpkts;
  56         u32                     last_outpkts;
  57         u64                     last_inbytes;
  58         u64                     last_outbytes;
  59
  60         u32                     cps;
  61         u32                     inpps;
  62         u32                     outpps;
  63         u32                     inbps;
  64         u32                     outbps;
  65 };
  66
  67
  68 static struct ip_vs_estimator *est_list = NULL;
  69 static DEFINE_RWLOCK(est_lock);
  70 static struct timer_list est_timer;
  71
  72 static void estimation_timer(unsigned long arg)
  73 {
  74         struct ip_vs_estimator *e;
  75         struct ip_vs_stats *s;
  76         u32 n_conns;
  77         u32 n_inpkts, n_outpkts;
  78         u64 n_inbytes, n_outbytes;
  79         u32 rate;
  80
  81         read_lock(&est_lock);
  82         for (e = est_list; e; e = e->next) {
  83                 s = e->stats;
  84
  85                 spin_lock(&s->lock);
  86                 n_conns = s->conns;
  87                 n_inpkts = s->inpkts;
  88                 n_outpkts = s->outpkts;
  89                 n_inbytes = s->inbytes;
  90                 n_outbytes = s->outbytes;
  91
  92                 /* scaled by 2^10, but divided 2 seconds */
  93                 rate = (n_conns - e->last_conns)<<9;
  94                 e->last_conns = n_conns;
  95                 e->cps += ((long)rate - (long)e->cps)>>2;
  96                 s->cps = (e->cps+0x1FF)>>10;
  97
  98                 rate = (n_inpkts - e->last_inpkts)<<9;
  99                 e->last_inpkts = n_inpkts;
 100                 e->inpps += ((long)rate - (long)e->inpps)>>2;
 101                 s->inpps = (e->inpps+0x1FF)>>10;
 102
 103                 rate = (n_outpkts - e->last_outpkts)<<9;
 104                 e->last_outpkts = n_outpkts;
 105                 e->outpps += ((long)rate - (long)e->outpps)>>2;
 106                 s->outpps = (e->outpps+0x1FF)>>10;
 107
 108                 rate = (n_inbytes - e->last_inbytes)<<4;
 109                 e->last_inbytes = n_inbytes;
 110                 e->inbps += ((long)rate - (long)e->inbps)>>2;
 111                 s->inbps = (e->inbps+0xF)>>5;
 112
 113                 rate = (n_outbytes - e->last_outbytes)<<4;
 114                 e->last_outbytes = n_outbytes;
 115                 e->outbps += ((long)rate - (long)e->outbps)>>2;
 116                 s->outbps = (e->outbps+0xF)>>5;
 117                 spin_unlock(&s->lock);
 118         }
 119         read_unlock(&est_lock);
 120         mod_timer(&est_timer, jiffies + 2*HZ);
 121 }
 122
 123 int ip_vs_new_estimator(struct ip_vs_stats *stats)
 124 {
 125         struct ip_vs_estimator *est;
 126
 127         est = kmalloc(sizeof(*est), GFP_KERNEL);
 128         if (est == NULL)
 129                 return -ENOMEM;
 130
 131         memset(est, 0, sizeof(*est));
 132         est->stats = stats;
 133         est->last_conns = stats->conns;
 134         est->cps = stats->cps<<10;
 135
 136         est->last_inpkts = stats->inpkts;
 137         est->inpps = stats->inpps<<10;
 138
 139         est->last_outpkts = stats->outpkts;
 140         est->outpps = stats->outpps<<10;
 141
 142         est->last_inbytes = stats->inbytes;
 143         est->inbps = stats->inbps<<5;
 144
 145         est->last_outbytes = stats->outbytes;
 146         est->outbps = stats->outbps<<5;
 147
 148         write_lock_bh(&est_lock);
 149         est->next = est_list;
 150         if (est->next == NULL) {
 151                 init_timer(&est_timer);
 152                 est_timer.expires = jiffies + 2*HZ;
 153                 est_timer.function = estimation_timer;
 154                 add_timer(&est_timer);
 155         }
 156         est_list = est;
 157         write_unlock_bh(&est_lock);
 158         return 0;
 159 }
 160
 161 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 162 {
 163         struct ip_vs_estimator *est, **pest;
 164         int killed = 0;
 165
 166         write_lock_bh(&est_lock);
 167         pest = &est_list;
 168         while ((est=*pest) != NULL) {
 169                 if (est->stats != stats) {
 170                         pest = &est->next;
 171                         continue;
 172                 }
 173                 *pest = est->next;
 174                 kfree(est);
 175                 killed++;
 176         }
 177         if (killed && est_list == NULL)
 178                 del_timer_sync(&est_timer);
 179         write_unlock_bh(&est_lock);
 180 }
 181
 182 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 183 {
 184         struct ip_vs_estimator *e;
 185
 186         write_lock_bh(&est_lock);
 187         for (e = est_list; e; e = e->next) {
 188                 if (e->stats != stats)
 189                         continue;
 190
 191                 /* set counters zero */
 192                 e->last_conns = 0;
 193                 e->last_inpkts = 0;
 194                 e->last_outpkts = 0;
 195                 e->last_inbytes = 0;
 196                 e->last_outbytes = 0;
 197                 e->cps = 0;
 198                 e->inpps = 0;
 199                 e->outpps = 0;
 200                 e->inbps = 0;
 201                 e->outbps = 0;
 202         }
 203         write_unlock_bh(&est_lock);
 204 }