[antlr-interest] Re: Java memory mapped IO is slow for big files :(

[John D. Mitchell]

>>>>> "lgcraymer" == lgcraymer  <lgc at mail1.jpl.nasa.gov> writes:
>>>>>>> "Terence" == Terence Parr <parrt at c...> writes:
[...]

> If you take a closer look at Ter's data, it looks like the conclusion is
> that a = c[n] // c is a character array is noticeably slower than a =
> X.read().

> That might be due to bounds checking, array indexing, and/or something
> else; it's not a disk issue because the three tests are more-or-less
> equivalent in terms of disk usage.

I'm not clear on that because it's unclear from Ter's message exactly what
he was (really :-) doing.  Perhaps he can put his test programs up so we
can check them out.

For example, allocating a huge array (and zeroing it), filling it, and then
iterating through it (and keeping the data around) is a bit different than
just BufferedReader'ing your way through a file and throwing away the data.

Thanks,
	John


 
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