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



NAME
       Smokeping::matchers::Avgratio - detect changes in average median
       latency

OVERVIEW
       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.

DESCRIPTION
       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

EXAMPLE
       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.

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

SPONSORSHIP
       The development of this matcher has been sponsored by Virtela Communi-
       cations, <http://www.virtela.net/>.

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 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.

AUTHOR
       Tobias Oetiker <tobi@oetiker.ch>



2.4.2                             2005-03-11  Smokeping::matchers::Avgratio(3)
