Smokeping::matchers::Avgratio(3)   SmokePing  Smokeping::matchers::Avgratio(3)



NNAAMMEE
       Smokeping::matchers::Avgratio - detect changes in average median
       latency

OOVVEERRVVIIEEWW
       The Avgratio matcher establishes a historic average median latency over
       several measurement rounds. It compares this average, against a second
       average latency value again build over several rounds of measurement.

DDEESSCCRRIIPPTTIIOONN
       Call the matcher with the following sequence:

        type = matcher
        pattern =  Avgratio(historic=>a,current=>b,comparator=>o,percentage=>p)

       historic
           The number of median values to use for building the 'historic'
           average.

       current
           The number of median values to use for building the 'current' aver-
           age.

       comparator
           Which comparison operator should be used to compare current/his-
           toric with percentage.

       percentage
           Right hand side of the comparison.

         old <--- historic ---><--- current ---> now

EEXXAAMMPPLLEE
       Take build the average median latency over 10 samples, use this to
       divide the current average latency built over 2 samples and check if it
       is bigger than 150%.

        Avgratio(historic=>10,current=>2,comparator=>'>',percentage=>150);

        avg(current)/avg(historic) > 150/100

       This means the matcher will activate when the current latency average
       is more than 1.5 times the historic latency average established over
       the last 10 rounds of measurement.

CCOOPPYYRRIIGGHHTT
       Copyright (c) 2004 by OETIKER+PARTNER AG. All rights reserved.

SSPPOONNSSOORRSSHHIIPP
       The development of this matcher has been sponsored by Virtela Communi-
       cations, <http://www.virtela.net/>.

LLIICCEENNSSEE
       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 MER-
       CHANTABILITY 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.

AAUUTTHHOORR
       Tobias Oetiker <tobi@oetiker.ch>



2.3.6                             2005-03-11  Smokeping::matchers::Avgratio(3)
