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1<!doctype linuxdoc system>
2
3<article>
4
5<title>RTACCT Utility
6<author>Robert Olsson
7<date>some_negative_number, 20 Dec 2001
8
9<p>
10Here is some code for monitoring the route cache. For systems handling high
11network load, servers, routers, firewalls etc the route cache and its garbage
12collection is crucial. Linux has a solid implementation.
13
14<p>
15The kernel patch (not required since linux-2.4.7) adds statistics counters
16from route cache process into
17/proc/net/rt_cache_stat. A companion user mode program presents the statistics
18in a vmstat or iostat manner. The ratio between cache hits and misses gives
19the flow length.
20
21<p>
22Hopefully it can help understanding performance and DoS and other related
23issues.
24
25<p> An URL where newer versions of this utility can be (probably) found
26is ftp://robur.slu.se/pub/Linux/net-development/rt_cache_stat/
27
28
29<p><bf/Description/
30
31<p>The format of the command is:
32
33<tscreen><verb>
34       rtstat [ OPTIONS ]
35</verb></tscreen>
36
37<p> <tt/OPTIONS/ are:
38
39<itemize>
40
41<item><tt/-h/, <tt/-help/ - show help page and version of the utility.
42
43<item><tt/-i INTERVAL/ - interval between snapshots, default value is
442 seconds.
45
46<item><tt/-s NUMBER/ - whether to print header line. 0 inhibits header line,
471 prescribes to print it once and 2 (this is default setting) forces header
48line each 20 lines.
49
50</itemize>
51
52</article>
53