+++ /dev/null
-/*
- * net/sched/estimator.c Simple rate estimator.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- *
- * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
- */
-
-#include <asm/uaccess.h>
-#include <asm/system.h>
-#include <linux/bitops.h>
-#include <linux/module.h>
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/jiffies.h>
-#include <linux/string.h>
-#include <linux/mm.h>
-#include <linux/socket.h>
-#include <linux/sockios.h>
-#include <linux/in.h>
-#include <linux/errno.h>
-#include <linux/interrupt.h>
-#include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <linux/rtnetlink.h>
-#include <linux/init.h>
-#include <net/sock.h>
-#include <net/pkt_sched.h>
-
-/*
- This code is NOT intended to be used for statistics collection,
- its purpose is to provide a base for statistical multiplexing
- for controlled load service.
- If you need only statistics, run a user level daemon which
- periodically reads byte counters.
-
- Unfortunately, rate estimation is not a very easy task.
- F.e. I did not find a simple way to estimate the current peak rate
- and even failed to formulate the problem 8)8)
-
- So I preferred not to built an estimator into the scheduler,
- but run this task separately.
- Ideally, it should be kernel thread(s), but for now it runs
- from timers, which puts apparent top bounds on the number of rated
- flows, has minimal overhead on small, but is enough
- to handle controlled load service, sets of aggregates.
-
- We measure rate over A=(1<<interval) seconds and evaluate EWMA:
-
- avrate = avrate*(1-W) + rate*W
-
- where W is chosen as negative power of 2: W = 2^(-ewma_log)
-
- The resulting time constant is:
-
- T = A/(-ln(1-W))
-
-
- NOTES.
-
- * The stored value for avbps is scaled by 2^5, so that maximal
- rate is ~1Gbit, avpps is scaled by 2^10.
-
- * Minimal interval is HZ/4=250msec (it is the greatest common divisor
- for HZ=100 and HZ=1024 8)), maximal interval
- is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals
- are too expensive, longer ones can be implemented
- at user level painlessly.
- */
-
-#define EST_MAX_INTERVAL 5
-
-struct qdisc_estimator
-{
- struct qdisc_estimator *next;
- struct tc_stats *stats;
- spinlock_t *stats_lock;
- unsigned interval;
- int ewma_log;
- u64 last_bytes;
- u32 last_packets;
- u32 avpps;
- u32 avbps;
-};
-
-struct qdisc_estimator_head
-{
- struct timer_list timer;
- struct qdisc_estimator *list;
-};
-
-static struct qdisc_estimator_head elist[EST_MAX_INTERVAL+1];
-
-/* Estimator array lock */
-static DEFINE_RWLOCK(est_lock);
-
-static void est_timer(unsigned long arg)
-{
- int idx = (int)arg;
- struct qdisc_estimator *e;
-
- read_lock(&est_lock);
- for (e = elist[idx].list; e; e = e->next) {
- struct tc_stats *st = e->stats;
- u64 nbytes;
- u32 npackets;
- u32 rate;
-
- spin_lock(e->stats_lock);
- nbytes = st->bytes;
- npackets = st->packets;
- rate = (nbytes - e->last_bytes)<<(7 - idx);
- e->last_bytes = nbytes;
- e->avbps += ((long)rate - (long)e->avbps) >> e->ewma_log;
- st->bps = (e->avbps+0xF)>>5;
-
- rate = (npackets - e->last_packets)<<(12 - idx);
- e->last_packets = npackets;
- e->avpps += ((long)rate - (long)e->avpps) >> e->ewma_log;
- e->stats->pps = (e->avpps+0x1FF)>>10;
- spin_unlock(e->stats_lock);
- }
-
- mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
- read_unlock(&est_lock);
-}
-
-int qdisc_new_estimator(struct tc_stats *stats, spinlock_t *stats_lock, struct rtattr *opt)
-{
- struct qdisc_estimator *est;
- struct tc_estimator *parm = RTA_DATA(opt);
-
- if (RTA_PAYLOAD(opt) < sizeof(*parm))
- return -EINVAL;
-
- if (parm->interval < -2 || parm->interval > 3)
- return -EINVAL;
-
- est = kzalloc(sizeof(*est), GFP_KERNEL);
- if (est == NULL)
- return -ENOBUFS;
-
- est->interval = parm->interval + 2;
- est->stats = stats;
- est->stats_lock = stats_lock;
- est->ewma_log = parm->ewma_log;
- est->last_bytes = stats->bytes;
- est->avbps = stats->bps<<5;
- est->last_packets = stats->packets;
- est->avpps = stats->pps<<10;
-
- est->next = elist[est->interval].list;
- if (est->next == NULL) {
- init_timer(&elist[est->interval].timer);
- elist[est->interval].timer.data = est->interval;
- elist[est->interval].timer.expires = jiffies + ((HZ<<est->interval)/4);
- elist[est->interval].timer.function = est_timer;
- add_timer(&elist[est->interval].timer);
- }
- write_lock_bh(&est_lock);
- elist[est->interval].list = est;
- write_unlock_bh(&est_lock);
- return 0;
-}
-
-void qdisc_kill_estimator(struct tc_stats *stats)
-{
- int idx;
- struct qdisc_estimator *est, **pest;
-
- for (idx=0; idx <= EST_MAX_INTERVAL; idx++) {
- int killed = 0;
- pest = &elist[idx].list;
- while ((est=*pest) != NULL) {
- if (est->stats != stats) {
- pest = &est->next;
- continue;
- }
-
- write_lock_bh(&est_lock);
- *pest = est->next;
- write_unlock_bh(&est_lock);
-
- kfree(est);
- killed++;
- }
- if (killed && elist[idx].list == NULL)
- del_timer(&elist[idx].timer);
- }
-}
-
-EXPORT_SYMBOL(qdisc_kill_estimator);
-EXPORT_SYMBOL(qdisc_new_estimator);