Re: [Patch] Always include <linux/types.h>

[Alexey Dobriyan]

On Wed, Nov 05, 2008 at 08:16:29PM +0100, Jörn Engel wrote:
> [ Threading should have been broken.  Doh! ]
> 
> On Wed, 5 November 2008 20:23:12 +0300, Alexey Dobriyan wrote:
> > On Wed, Nov 05, 2008 at 05:39:41PM +0100, Jörn Engel wrote:
> > > Hardly any file in the kernel can be compiled without including
> > > <linux/types.h>, directly or indirectly.  And I'd wager a beer that
> > > noone can find a non-trivial example.  I couldn't.
> > 
> > This is only going to slow down compilation and types.h is not causing much
> > compilation problems, in fact, I can't recall a compilation problem due to
> > types.h. Contary to config.h situation which was a pain.
> 
> My hope was actually to speed up compilation.  If the average c file
> includes 10 headers, on types.h will get included by most of them,
> possibly multiple times.  Each run after the first still has to parse
> the whole file, just to drop everything between  #ifndef _LINUX_TYPES_H
> and #endif.
> 
> By passing types.h on the command line we can drop it from all headers
> and only have to parse it once.  Just the intermediate step of parsing
> types.h 11 times instead of 10 will slow things down.  By about .4% on
> my not very beefy notebook.
> 
> Before:
> real    4m33.241s
> user    3m58.524s
> sys     0m18.539s
> 
> After:
> real    4m29.707s
> user    3m59.674s
> sys     0m18.182s

Could be anything.
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