[PATCH] Do not break buffers in fvwrite for unbuffered files

[Federico Terraneo]

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On 10/21/2013 05:36 PM, Corinna Vinschen wrote:
> On Oct 21 16:15, Federico wrote:
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>> 
>> On 10/21/2013 02:47 PM, Corinna Vinschen wrote:
>>> 
>>> Maye it makes sense to use the largest multiple  of BUFSIZ <= 
>>> MAX_INT. See below.
>>>> 
>>>> I'm wondering if it makes sense to avoid splitting writes
>>>> (and reads) also for buffered files. glibc appears to do it,
>>> 
>>> Buffered writes are already split into fp->_bf._size chunks. 
>>> Glibc basically uses the largest multiple of fp->_bf._size <=
>>> len instead. We could do the same.  Would you like to create a
>>> patch for that?
>> 
>> I'll have a look at what can be done in the next days.
> 
> Thanks!

Sorry for the delay, I've been quite busy.

Anyway, here's the patch that makes both unbuffered and fully buffered
writes faster. It writes in multiples of fp->_bf._size, and clamps at
INT_MAX, as requested.

Here's the changelog entry:

2013-10-31  Terraneo Federico  <fede.tft@hotmail.it>

	* libc/stdio/fvwrite.c: Allow writing in multiples of
	 fp->_bf._size for fully buffered and unbuffered files,
	 to improve write performance.

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