I agree that multiple cores will not help because there is a blocking point of the sequential read of the input file.

I am not so sure about output buffering. I really don't know in this situation, but depending upon the file system and other factors like the intelligence of the disk controller, increasing the buffer size for write could make a difference?
PerlO::buffersize
Just an idea to try. I would benchmark 64K vs standard size (which I guess is probably 4K) and see if there is any significant difference.

In reply to Re^2: Multithreading a large file split to multiple files by Marshall
in thread Multithreading a large file split to multiple files by 10isitch

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