Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * net/sched/gen_estimator.c Simple rate estimator. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version |
| 7 | * 2 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> |
| 10 | * |
| 11 | * Changes: |
| 12 | * Jamal Hadi Salim - moved it to net/core and reshulfed |
| 13 | * names to make it usable in general net subsystem. |
| 14 | */ |
| 15 | |
| 16 | #include <asm/uaccess.h> |
| 17 | #include <asm/system.h> |
Jiri Slaby | 1977f03 | 2007-10-18 23:40:25 -0700 | [diff] [blame^] | 18 | #include <linux/bitops.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/module.h> |
| 20 | #include <linux/types.h> |
| 21 | #include <linux/kernel.h> |
| 22 | #include <linux/jiffies.h> |
| 23 | #include <linux/string.h> |
| 24 | #include <linux/mm.h> |
| 25 | #include <linux/socket.h> |
| 26 | #include <linux/sockios.h> |
| 27 | #include <linux/in.h> |
| 28 | #include <linux/errno.h> |
| 29 | #include <linux/interrupt.h> |
| 30 | #include <linux/netdevice.h> |
| 31 | #include <linux/skbuff.h> |
| 32 | #include <linux/rtnetlink.h> |
| 33 | #include <linux/init.h> |
| 34 | #include <net/sock.h> |
| 35 | #include <net/gen_stats.h> |
| 36 | |
| 37 | /* |
| 38 | This code is NOT intended to be used for statistics collection, |
| 39 | its purpose is to provide a base for statistical multiplexing |
| 40 | for controlled load service. |
| 41 | If you need only statistics, run a user level daemon which |
| 42 | periodically reads byte counters. |
| 43 | |
| 44 | Unfortunately, rate estimation is not a very easy task. |
| 45 | F.e. I did not find a simple way to estimate the current peak rate |
| 46 | and even failed to formulate the problem 8)8) |
| 47 | |
| 48 | So I preferred not to built an estimator into the scheduler, |
| 49 | but run this task separately. |
| 50 | Ideally, it should be kernel thread(s), but for now it runs |
| 51 | from timers, which puts apparent top bounds on the number of rated |
| 52 | flows, has minimal overhead on small, but is enough |
| 53 | to handle controlled load service, sets of aggregates. |
| 54 | |
| 55 | We measure rate over A=(1<<interval) seconds and evaluate EWMA: |
| 56 | |
| 57 | avrate = avrate*(1-W) + rate*W |
| 58 | |
| 59 | where W is chosen as negative power of 2: W = 2^(-ewma_log) |
| 60 | |
| 61 | The resulting time constant is: |
| 62 | |
| 63 | T = A/(-ln(1-W)) |
| 64 | |
| 65 | |
| 66 | NOTES. |
| 67 | |
| 68 | * The stored value for avbps is scaled by 2^5, so that maximal |
| 69 | rate is ~1Gbit, avpps is scaled by 2^10. |
| 70 | |
| 71 | * Minimal interval is HZ/4=250msec (it is the greatest common divisor |
| 72 | for HZ=100 and HZ=1024 8)), maximal interval |
| 73 | is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals |
| 74 | are too expensive, longer ones can be implemented |
| 75 | at user level painlessly. |
| 76 | */ |
| 77 | |
| 78 | #define EST_MAX_INTERVAL 5 |
| 79 | |
| 80 | struct gen_estimator |
| 81 | { |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 82 | struct list_head list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | struct gnet_stats_basic *bstats; |
| 84 | struct gnet_stats_rate_est *rate_est; |
| 85 | spinlock_t *stats_lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | int ewma_log; |
| 87 | u64 last_bytes; |
| 88 | u32 last_packets; |
| 89 | u32 avpps; |
| 90 | u32 avbps; |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 91 | struct rcu_head e_rcu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | }; |
| 93 | |
| 94 | struct gen_estimator_head |
| 95 | { |
| 96 | struct timer_list timer; |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 97 | struct list_head list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | }; |
| 99 | |
| 100 | static struct gen_estimator_head elist[EST_MAX_INTERVAL+1]; |
| 101 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 102 | /* Protects against NULL dereference */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | static DEFINE_RWLOCK(est_lock); |
| 104 | |
| 105 | static void est_timer(unsigned long arg) |
| 106 | { |
| 107 | int idx = (int)arg; |
| 108 | struct gen_estimator *e; |
| 109 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 110 | rcu_read_lock(); |
| 111 | list_for_each_entry_rcu(e, &elist[idx].list, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | u64 nbytes; |
| 113 | u32 npackets; |
| 114 | u32 rate; |
| 115 | |
| 116 | spin_lock(e->stats_lock); |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 117 | read_lock(&est_lock); |
| 118 | if (e->bstats == NULL) |
| 119 | goto skip; |
| 120 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | nbytes = e->bstats->bytes; |
| 122 | npackets = e->bstats->packets; |
| 123 | rate = (nbytes - e->last_bytes)<<(7 - idx); |
| 124 | e->last_bytes = nbytes; |
| 125 | e->avbps += ((long)rate - (long)e->avbps) >> e->ewma_log; |
| 126 | e->rate_est->bps = (e->avbps+0xF)>>5; |
| 127 | |
| 128 | rate = (npackets - e->last_packets)<<(12 - idx); |
| 129 | e->last_packets = npackets; |
| 130 | e->avpps += ((long)rate - (long)e->avpps) >> e->ewma_log; |
| 131 | e->rate_est->pps = (e->avpps+0x1FF)>>10; |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 132 | skip: |
| 133 | read_unlock(&est_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | spin_unlock(e->stats_lock); |
| 135 | } |
| 136 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 137 | if (!list_empty(&elist[idx].list)) |
Patrick McHardy | 6b25d30 | 2007-07-09 15:30:19 -0700 | [diff] [blame] | 138 | mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4)); |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 139 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | } |
| 141 | |
| 142 | /** |
| 143 | * gen_new_estimator - create a new rate estimator |
| 144 | * @bstats: basic statistics |
| 145 | * @rate_est: rate estimator statistics |
| 146 | * @stats_lock: statistics lock |
| 147 | * @opt: rate estimator configuration TLV |
| 148 | * |
| 149 | * Creates a new rate estimator with &bstats as source and &rate_est |
| 150 | * as destination. A new timer with the interval specified in the |
| 151 | * configuration TLV is created. Upon each interval, the latest statistics |
| 152 | * will be read from &bstats and the estimated rate will be stored in |
| 153 | * &rate_est with the statistics lock grabed during this period. |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 154 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | * Returns 0 on success or a negative error code. |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 156 | * |
| 157 | * NOTE: Called under rtnl_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | */ |
| 159 | int gen_new_estimator(struct gnet_stats_basic *bstats, |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 160 | struct gnet_stats_rate_est *rate_est, |
| 161 | spinlock_t *stats_lock, |
| 162 | struct rtattr *opt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | { |
| 164 | struct gen_estimator *est; |
| 165 | struct gnet_estimator *parm = RTA_DATA(opt); |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 166 | int idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | |
| 168 | if (RTA_PAYLOAD(opt) < sizeof(*parm)) |
| 169 | return -EINVAL; |
| 170 | |
| 171 | if (parm->interval < -2 || parm->interval > 3) |
| 172 | return -EINVAL; |
| 173 | |
Andrew Morton | 77d04bd | 2006-04-07 14:52:59 -0700 | [diff] [blame] | 174 | est = kzalloc(sizeof(*est), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | if (est == NULL) |
| 176 | return -ENOBUFS; |
| 177 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 178 | idx = parm->interval + 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | est->bstats = bstats; |
| 180 | est->rate_est = rate_est; |
| 181 | est->stats_lock = stats_lock; |
| 182 | est->ewma_log = parm->ewma_log; |
| 183 | est->last_bytes = bstats->bytes; |
| 184 | est->avbps = rate_est->bps<<5; |
| 185 | est->last_packets = bstats->packets; |
| 186 | est->avpps = rate_est->pps<<10; |
| 187 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 188 | if (!elist[idx].timer.function) { |
| 189 | INIT_LIST_HEAD(&elist[idx].list); |
| 190 | setup_timer(&elist[idx].timer, est_timer, idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | } |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 192 | |
| 193 | if (list_empty(&elist[idx].list)) |
| 194 | mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4)); |
| 195 | |
| 196 | list_add_rcu(&est->list, &elist[idx].list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | return 0; |
| 198 | } |
| 199 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 200 | static void __gen_kill_estimator(struct rcu_head *head) |
| 201 | { |
| 202 | struct gen_estimator *e = container_of(head, |
| 203 | struct gen_estimator, e_rcu); |
| 204 | kfree(e); |
| 205 | } |
| 206 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | /** |
| 208 | * gen_kill_estimator - remove a rate estimator |
| 209 | * @bstats: basic statistics |
| 210 | * @rate_est: rate estimator statistics |
| 211 | * |
| 212 | * Removes the rate estimator specified by &bstats and &rate_est |
| 213 | * and deletes the timer. |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 214 | * |
| 215 | * NOTE: Called under rtnl_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | */ |
| 217 | void gen_kill_estimator(struct gnet_stats_basic *bstats, |
| 218 | struct gnet_stats_rate_est *rate_est) |
| 219 | { |
| 220 | int idx; |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 221 | struct gen_estimator *e, *n; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | |
| 223 | for (idx=0; idx <= EST_MAX_INTERVAL; idx++) { |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 224 | |
| 225 | /* Skip non initialized indexes */ |
| 226 | if (!elist[idx].timer.function) |
| 227 | continue; |
| 228 | |
| 229 | list_for_each_entry_safe(e, n, &elist[idx].list, list) { |
| 230 | if (e->rate_est != rate_est || e->bstats != bstats) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | |
| 233 | write_lock_bh(&est_lock); |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 234 | e->bstats = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | write_unlock_bh(&est_lock); |
| 236 | |
Ranko Zivojnovic | 0929c2d | 2007-07-16 18:28:32 -0700 | [diff] [blame] | 237 | list_del_rcu(&e->list); |
| 238 | call_rcu(&e->e_rcu, __gen_kill_estimator); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | } |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * gen_replace_estimator - replace rate estimator configruation |
| 245 | * @bstats: basic statistics |
| 246 | * @rate_est: rate estimator statistics |
| 247 | * @stats_lock: statistics lock |
| 248 | * @opt: rate estimator configuration TLV |
| 249 | * |
| 250 | * Replaces the configuration of a rate estimator by calling |
| 251 | * gen_kill_estimator() and gen_new_estimator(). |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 252 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | * Returns 0 on success or a negative error code. |
| 254 | */ |
| 255 | int |
| 256 | gen_replace_estimator(struct gnet_stats_basic *bstats, |
| 257 | struct gnet_stats_rate_est *rate_est, spinlock_t *stats_lock, |
| 258 | struct rtattr *opt) |
| 259 | { |
| 260 | gen_kill_estimator(bstats, rate_est); |
| 261 | return gen_new_estimator(bstats, rate_est, stats_lock, opt); |
| 262 | } |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 263 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | |
| 265 | EXPORT_SYMBOL(gen_kill_estimator); |
| 266 | EXPORT_SYMBOL(gen_new_estimator); |
| 267 | EXPORT_SYMBOL(gen_replace_estimator); |