[Beowulf] Measurement of TCP traffic between nodes
kus at free.net
Wed Mar 23 11:13:13 PST 2005
I want to measure message sizes (and "frequencies" of messages
exchanges) between cluster nodes under parallelization of
some applications. These applications use parallelization tools
working over TCP (Linda, DDI), so I need to know the size of TCP
packages and the number of TCP packages per second.
1) There is no other traffic on the corresponding interfaces,
and (at least for 2-nodes "subcluster"; it's used for simplicity) I
may use simple ifconfig output (in a loop). Do I understand correctly,
the number of bytes transmitted at "application level" is
something about (for example for transmission)
Tx_bytes - TX_packets*40 ?
(i.e. a) there is no bytes from ethernet headers - in ifconfig output
b) the number of application transmitted bytes per TCP packet =
size_of_packet - 40 (in average))
2) Are the tools like tcpdump better for this task (pls
take into account that I need only timestamps and data sizes) ?
Zelinsky Institute of Organic Chemistry
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