1/*
2 * ip_vs_est.c: simple rate estimator for IPVS
3 *
4 * Version:     $Id: ip_vs_est.c,v 1.1.1.1 2007/08/03 18:53:51 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
48struct 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
67static struct ip_vs_estimator *est_list = NULL;
68static DEFINE_RWLOCK(est_lock);
69static struct timer_list est_timer;
70
71static 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
122int 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
159void 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
180void 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}
203