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From: Martin Gregorie <martin@address-in-sig.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: byte stream vs char stream buffer
Date: Sun, 11 May 2014 09:05:16 +0000 (UTC)
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On Sat, 10 May 2014 17:21:19 -0700, Roedy Green wrote:

> On Sat, 10 May 2014 23:24:57 +0200, Robert Klemme
> <shortcutter@googlemail.com> wrote, quoted or indirectly quoted someone
> who said :
> 
>>I don't think duplicate buffering will make things better.
> 
> It does. And allocating your space exactly 50:50 makes a noticeable
> difference.
> 
> the plain Buffered reader was done like this:
> 
> final BufferedReader ibr = new BufferedReader( new FileReader(
> sampleDataFile ), buffsize / 2 );
>
You said earlier that you were partitioning a fixed amount of buffer 
space between the BufferedInputStream and the BufferedReader, but that's 
not what your code shows.

Instead the BufferedInputStream  is getting part of a 'buffer space 
allocation', which is set to 32K. This part varies from 10% to 90% of the 
32K while the BufferedReader always gets 16K. This means that the total 
buffer space used by the combination of BufferedInputStream and 
BufferedReader varies from 19.2 KB to 60.8 KB as the 'ratio' varies from 
0.1 to 0.9. 

In other words, you're not measuring what you thought you're measuring 
because the total buffer space used by each test varies by a factor of 
three during the tests and will almost certainly affect your results.



-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |