Re: thread mystery

On Wednesday 05 July 2006 17:30, [e-mail] wrote:
> any idea why this script slows downs drastically as it runs and seems to
> leak memory?

Slow compared to what?  Number of calls per second?

Creating threads and synchronizing is computationally expensive.  I'm not 
aware of any language where this isn't true, especially for synchronization. 
In your code, you incur a 28x lag per call by synchronizing with the sync 
library, and another 14x lag lag per call with the thread creation.*

It looks (from a later email) like you found the memory leak.

--- SER

(*) 	N=100000

	a=Time.now
	N.times { synchronize( :EX ) { k = 2 + 2 } }
	b=Time.now
	N.times { k = 2 + 2 }
	c=Time.now
	puts "Synchronize overhead: #{(b-a)/(c-b)}"

	S = Struct.new("S", :k)
	a=Time.now
	N.times { k = Thread.new {} }
	b=Time.now
	N.times { k = S.new {} }
	c=Time.now
	puts "Thread overhead: #{(b-a)/(c-b)}"

Provide a sufficiently large value of N to mask the overhead of the loop 
itself.

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