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> 10 Here is some code for monitoring the route cache. For systems handling high 11 network load, servers, routers, firewalls etc the route cache and its garbage 12 collection is crucial. Linux has a solid implementation. 13 14 <p> 15 The kernel patch (not required since linux-2.4.7) adds statistics counters 16 from route cache process into 17 /proc/net/rt_cache_stat. A companion user mode program presents the statistics 18 in a vmstat or iostat manner. The ratio between cache hits and misses gives 19 the flow length. 20 21 <p> 22 Hopefully it can help understanding performance and DoS and other related 23 issues. 24 25 <p> An URL where newer versions of this utility can be (probably) found 26 is 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 44 2 seconds. 45 46 <item><tt/-s NUMBER/ - whether to print header line. 0 inhibits header line, 47 1 prescribes to print it once and 2 (this is default setting) forces header 48 line each 20 lines. 49 50 </itemize> 51 52 </article> 53
