Re: gpars for calculating directory content size

[Russel Winder]

On Fri, 2017-06-16 at 14:55 +, Merlin Beedell wrote:
> I see that groovy has a handy method to return the sum of file & sub-
> directory sizes in a directory:
> new File('sample').directorySize()
> 
> But I would be interested to see if the underlying code uses gpars -
> on the assumption that the computation would be faster if sub-
> directories are found (the sum of each being performed in parallel).

No it just uses eachFileRecurse which is a single threaded recursive
walk over a file system.

 |> time du -s .
340380  .

real0m0.033s
user0m0.007s
sys 0m0.026s

|> time groovy -e "println(new File('.').directorySize())"
332167942

real0m1.215s
user0m2.081s
sys 0m0.169s

I am sure you could do a fork/join version of eachFileRecurse, but I am
not sure there is one.

[…]
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gpars for calculating directory content size

[Merlin Beedell]

I see that groovy has a handy method to return the sum of file & sub-directory 
sizes in a directory:
new File('sample').directorySize()

But I would be interested to see if the underlying code uses gpars - on the 
assumption that the computation would be faster if sub-directories are found 
(the sum of each being performed in parallel).

Actually - my interest is more in seeing a useful(?) example of gpars!

Merlin Beedell

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