Changes between Version 25 and Version 26 of PerformanceTesting


Ignore:
Timestamp:
11/11/11 10:58:44 (12 years ago)
Author:
Samuli Seppänen
Comment:

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  • PerformanceTesting

    v25 v26  
    344344[http://iperf.sourceforge.net/ Iperf] can be used to generate network traffic. It has previously been used to tune OpenVPN performance: look [wiki:Gigabit_Networks_Linux here].
    345345
    346 '''NOTE:''' if multiple clients are connecting simultaneously to an iperf server, the delay in connection establishment can be considerable. For example, a 30 second iperf burst with 20 clients can take 72 seconds (for details look [wiki:PerformanceTesting#MP-2results here]).
    347 
    348346== Collecting data ==
    349347
    350348[https://github.com/dagwieers/dstat Dstat] can be used to gather detailed resource utilization statistics on the server side.
    351349
    352 
     350= Notes =
     351
     352When the number of clients was increased, the incapability of the server processes - especially iperf - to establish new connections quickly started to show with as few as 20 clients. This was clearly visible when looking at server-side iperf output: clients connected with delay of several seconds. This had two effects:
     353
     354 * Prolonging the subtests (e.g. 10 second test could become 20+ second test)
     355 * Artificially increased the average client bandwidth due to the head and tail of clients that had less competition (bandwidth-vise)
     356
     357OpenVPN connection initialization seems to go much faster.