[Spread-users] Spread performance
jschultz at spreadconcepts.com
Tue May 25 15:01:45 EDT 2004
Pau Artigas wrote:
> Is this the expected performance/behaviour?
The behavior you describe is expected in Spread 3. When a daemon sends
a message it sends it "locally" through UDP broadcast and directly to
the representative (the first listed daemon in the segment that is
participating in that daemon membership) of each of the other segments.
No traffic pruning is done based on whether or not the different
segments have users in a group or not. You probably could develop a
method that would do this pruning but Spread currently does not.
Also, after sending traffic, the control token of the daemons continues
to circulate around the ring for a bit (by default I believe) -- the
expectation being that there exists a "locality of reference" of
traffic: once some traffic is sent it is highly likely that more traffic
will follow soon after; conversly when no traffic has been sent for a
while it is likely that the system will remain dormant for a period of
time, so the token should stop circulating.
It is hard for me to say if the performance you got is expected or not,
especially since you didn't tell us what it was :) To make a guess at
that we'd have to know what the network links between the different
sites looks like in terms of latency/throughput/loss rate. In the past,
I believe (correct me if I'm wrong CNDS) that with Spread 3 we have
pushed approx. 1-3 Mbit/s in a wide area configuration with several
sites stretching across the USA.
> Is the spread.conf ok?
Looks ok to me as long as you are actually using different IP addresses
for the multicast/broadcast address and the machine addresses in your
> Does spread need a warmup to create optimum distribution routes?
Spread 3 does not use any optimized distribution routes. It uses the
simple heurstic I stated above and a token ring for passing a control
token. It does take some time to establish daemon memberships (the
token ring) before client communications are sent.
> I'm doing something wrong?
Not that I can tell.
John Lane Schultz
Spread Concepts LLC
Phn: 443 838 2200
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