[erlang-questions] Strange multi-core result on windows.

Ian <>
Mon Nov 28 23:12:04 CET 2011


Hi All,

[Snip a lot of interesting replies. ]

Thanks everyone for the information.

The version of Windows in version 7 Prof. 64 bit.  The version of Erlang 
is werl -
Erlang R14B04 (erts-5.8.5) [smp:4:4] [rq:4] [async-threads:0]
Eshell V5.8.5  (abort with ^G)

Having thought a bit more this is what I guess is happening.

Process 1 starts and reads the data and queues up a lot (2MB) of 
messages for process 2.
Process 2 is the heavy one. It trickles (relatively speaking) messages 
out to process 3.
3 passes them on to 4 before 2 has generated the next message.
4 is very light, and hardly does anything.

So after an initial blip, things settle down to one core running process 
2, and two other cores coping with 3 and 4, but not working very hard.

What I am astonished at is the overall speed of Erlang! Its not C - but 
it gives C a run for its money.

I'll chase up percept when I have some time.

Thanks again for your input.

Ian










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