Well, quite possible, I may have misinterpreted the OP. However the OP specifically said: 

I have a program that reads and processes approximately 8 million line
+s of data. For each line read it does:

my @aa = split(/\t/);
@{$ref}{@head} = @aa;

[download]
It seems to indicate that the program is executing the two lines of code above for each of the 8 million lines of input. Quite possibly the program may be doing something else, but this was just exactly what I was asking for, more code if any.

In reply to Re^5: Faster Hash Slices by Laurent_R
in thread Faster Hash Slices by jht

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