net/ipv4/ipvs/ip_vs_est.c

   1 /*
   2  * ip_vs_est.c: simple rate estimator for IPVS
   3  *
   4  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  *
  11  * Changes:
  12  *
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/slab.h>
  17 #include <linux/types.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/sysctl.h>
  20 #include <linux/list.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 static void estimation_timer(unsigned long arg);
  49
  50 static LIST_HEAD(est_list);
  51 static DEFINE_SPINLOCK(est_lock);
  52 static DEFINE_TIMER(est_timer, estimation_timer, 0, 0);
  53
  54 static void estimation_timer(unsigned long arg)
  55 {
  56         struct ip_vs_estimator *e;
  57         struct ip_vs_stats *s;
  58         u32 n_conns;
  59         u32 n_inpkts, n_outpkts;
  60         u64 n_inbytes, n_outbytes;
  61         u32 rate;
  62
  63         spin_lock(&est_lock);
  64         list_for_each_entry(e, &est_list, list) {
  65                 s = container_of(e, struct ip_vs_stats, est);
  66
  67                 spin_lock(&s->lock);
  68                 n_conns = s->conns;
  69                 n_inpkts = s->inpkts;
  70                 n_outpkts = s->outpkts;
  71                 n_inbytes = s->inbytes;
  72                 n_outbytes = s->outbytes;
  73
  74                 /* scaled by 2^10, but divided 2 seconds */
  75                 rate = (n_conns - e->last_conns)<<9;
  76                 e->last_conns = n_conns;
  77                 e->cps += ((long)rate - (long)e->cps)>>2;
  78                 s->cps = (e->cps+0x1FF)>>10;
  79
  80                 rate = (n_inpkts - e->last_inpkts)<<9;
  81                 e->last_inpkts = n_inpkts;
  82                 e->inpps += ((long)rate - (long)e->inpps)>>2;
  83                 s->inpps = (e->inpps+0x1FF)>>10;
  84
  85                 rate = (n_outpkts - e->last_outpkts)<<9;
  86                 e->last_outpkts = n_outpkts;
  87                 e->outpps += ((long)rate - (long)e->outpps)>>2;
  88                 s->outpps = (e->outpps+0x1FF)>>10;
  89
  90                 rate = (n_inbytes - e->last_inbytes)<<4;
  91                 e->last_inbytes = n_inbytes;
  92                 e->inbps += ((long)rate - (long)e->inbps)>>2;
  93                 s->inbps = (e->inbps+0xF)>>5;
  94
  95                 rate = (n_outbytes - e->last_outbytes)<<4;
  96                 e->last_outbytes = n_outbytes;
  97                 e->outbps += ((long)rate - (long)e->outbps)>>2;
  98                 s->outbps = (e->outbps+0xF)>>5;
  99                 spin_unlock(&s->lock);
 100         }
 101         spin_unlock(&est_lock);
 102         mod_timer(&est_timer, jiffies + 2*HZ);
 103 }
 104
 105 void ip_vs_new_estimator(struct ip_vs_stats *stats)
 106 {
 107         struct ip_vs_estimator *est = &stats->est;
 108
 109         INIT_LIST_HEAD(&est->list);
 110
 111         est->last_conns = stats->conns;
 112         est->cps = stats->cps<<10;
 113
 114         est->last_inpkts = stats->inpkts;
 115         est->inpps = stats->inpps<<10;
 116
 117         est->last_outpkts = stats->outpkts;
 118         est->outpps = stats->outpps<<10;
 119
 120         est->last_inbytes = stats->inbytes;
 121         est->inbps = stats->inbps<<5;
 122
 123         est->last_outbytes = stats->outbytes;
 124         est->outbps = stats->outbps<<5;
 125
 126         spin_lock_bh(&est_lock);
 127         if (list_empty(&est_list))
 128                 mod_timer(&est_timer, jiffies + 2 * HZ);
 129         list_add(&est->list, &est_list);
 130         spin_unlock_bh(&est_lock);
 131 }
 132
 133 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 134 {
 135         struct ip_vs_estimator *est = &stats->est;
 136
 137         spin_lock_bh(&est_lock);
 138         list_del(&est->list);
 139         while (list_empty(&est_list) && try_to_del_timer_sync(&est_timer) < 0) {
 140                 spin_unlock_bh(&est_lock);
 141                 cpu_relax();
 142                 spin_lock_bh(&est_lock);
 143         }
 144         spin_unlock_bh(&est_lock);
 145 }
 146
 147 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 148 {
 149         struct ip_vs_estimator *est = &stats->est;
 150
 151         /* set counters zero, caller must hold the stats->lock lock */
 152         est->last_inbytes = 0;
 153         est->last_outbytes = 0;
 154         est->last_conns = 0;
 155         est->last_inpkts = 0;
 156         est->last_outpkts = 0;
 157         est->cps = 0;
 158         est->inpps = 0;
 159         est->outpps = 0;
 160         est->inbps = 0;
 161         est->outbps = 0;
 162 }