[Spread-users] Optimal message size.

Theo E. Schlossnagle jesus at omniti.com
Thu Aug 9 19:56:53 EDT 2001

Yair Amir wrote:
> Perhaps I did not understand your question. But if your messages are one order of magnitude larger than the Ethernet MTU (i.e. they are 5-10 KBytes) the best is to not split them and give them to Spread using one SP_multicast.
> Actually, for any size up to the max spread message, the best is not to split. The reason is that if you do not split, Spread optimizes its packets. If you do split unnecesarily, be aware that Spread will add a message header (pretty big - 80 - 100 bytes or so depending on the version and wide area support) to every "split" it gets.
> There is no relation between message size and memory footprint if the messages are large (5-10Kbytes). The relation is between (more or less) the total number of bytes that are pending (a different way to say - total number of spread packets).

I think you understand the message.  You answered my question!  There is an 
overhead (albeit small) for each message I send.. And Spread optimizes to fit 
in the MTU of the media you are running on (or at least for Ethernet), so I 
gain quite a bit by passing a 1MB message to SP_multicast (or as big as it 
will take).

Theo Schlossnagle
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2047R/33131B65/71 F7 95 64 49 76 5D BA  3D 90 B9 9F BE 27 24 E7

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