[Spread-users] sublinear movement

[Jonathan Stanton]

The token will continue to rotate while waiting for new 
messages to be generated. To prevent too much wasted bandwith with tokens 
doing now work, Spread stops rotating the token after 100 rotations that 
accomplish nothing and then switches to only sending the token if a daemon 
asks for it, or once a second or so. So the extra 45 tokens were valid 
tokens, but no real messages were sent during their cycle (the tokens do 
not carry any message content themselves). 

We are actually going to switch this in the next version so the token goes
in to 'idle' mode faster as people are often surprised that the token
rotates even when no messages are being sent.

I'm not sure about the exact packet counts you provide, but there is 
definitly some fixed overhead per spread message, and some extra traffic 
"per second" that will become less noticable the more messages you are 
sending per second.

Cheers,

Jonathan



On Wed, Feb 04, 2004 at 12:42:29PM +0100, Piotr Kozieradzki wrote:
> I test spread on 3 host (Linux debian, CPU: Pentium II, network 100Mb) 
> in one segment (LAN, ethernet)
> On each  host is one spread demon and one spread client . Each client 
> has 2 publisher  and two subscriber. So each program sends his messeges 
> to  other program (one publisher from host A sends messeges to 
> subscriber from B and one to subscriber from C, etc. )
> In first test I send 30 packet per second (200B each packet) from each 
> publisher.  But avarage trafific is about 160B / s (it is about 10 times 
> more than it shuold be).
> After that I change my program so each generate 300  pac sekond (200B 
> each packet) from each publisher , it generate trafic about 290B/s. Is 
> it correct?
> 
> The other test was I run One demon on host A and one client (spuser) on 
> the same host. ther was no other spread demon in network. On spuser  i 
> create group MY_GROUP and send to this group one message "Hello". I saw 
> about 45 annoucment from spread demon "Received token". Does it meen 
> that he received 45 packet?
> 
> Piotr Kozieradzki
> 
> 
> 
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-- 
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Jonathan R. Stanton         jonathan at cs.jhu.edu
Dept. of Computer Science   
Johns Hopkins University    
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