Median

# NAME

Smokeping::matchers::Median - Find persistant changes in latency

# OVERVIEW

The idea behind this matcher is to find sustained changes in latency.

The median matcher takes a number of past median latencies. It splits the latencies into two groups (old and new) and again finds the median for each groups. If the difference between the two medians is bigger than a certain value, it will give a match.

# DESCRIPTION

Call the matcher with the following sequence:

     type = matcher
     pattern =  Median(old=>x,new=>y,diff=>z)

This will create a matcher which consumes x+y latency-datapoints, builds the two medians and the matches if the difference between the median latency is larger than z seconds.

# COPYRIGHT

Copyright (c) 2004 by OETIKER+PARTNER AG. All rights reserved.

# LICENSE

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.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

# AUTHOR

Tobias Oetiker <tobi@oetiker.ch>