| <!doctype linuxdoc system> |
| |
| <article> |
| |
| <title>RTACCT Utility |
| <author>Robert Olsson |
| <date>some_negative_number, 20 Dec 2001 |
| |
| <p> |
| Here is some code for monitoring the route cache. For systems handling high |
| network load, servers, routers, firewalls etc the route cache and its garbage |
| collection is crucial. Linux has a solid implementation. |
| |
| <p> |
| The kernel patch (not required since linux-2.4.7) adds statistics counters |
| from route cache process into |
| /proc/net/rt_cache_stat. A companion user mode program presents the statistics |
| in a vmstat or iostat manner. The ratio between cache hits and misses gives |
| the flow length. |
| |
| <p> |
| Hopefully it can help understanding performance and DoS and other related |
| issues. |
| |
| <p> An URL where newer versions of this utility can be (probably) found |
| is ftp://robur.slu.se/pub/Linux/net-development/rt_cache_stat/ |
| |
| |
| <p><bf/Description/ |
| |
| <p>The format of the command is: |
| |
| <tscreen><verb> |
| rtstat [ OPTIONS ] |
| </verb></tscreen> |
| |
| <p> <tt/OPTIONS/ are: |
| |
| <itemize> |
| |
| <item><tt/-h/, <tt/-help/ - show help page and version of the utility. |
| |
| <item><tt/-i INTERVAL/ - interval between snapshots, default value is |
| 2 seconds. |
| |
| <item><tt/-s NUMBER/ - whether to print header line. 0 inhibits header line, |
| 1 prescribes to print it once and 2 (this is default setting) forces header |
| line each 20 lines. |
| |
| </itemize> |
| |
| </article> |
