RE: Large File support and blocks.

From: Linda Walsh (law@sgi.com)
Date: Fri Sep 01 2000 - 02:09:23 EST

Perhaps an "easy" way to go would be to convert block numbers to
type "block_nr_t", then one could measure the difference that 10's of
nanoseconds make against seeks and reads of disk data.

Obviously the effect would be greater on ramdisks, but on computers with
equivalent generation hard disks we might be talking something non-measurable
or at least down in the noise level. Even transfers of 512 bytes of
data from a buffer to user space is going to take significantly more cycles.

If the change became as simple as changing a typedef in a file, then you
could even allow a user to choose to allow "very large files" -- compiling
with long long when turned on, or simple ints when turned off -- if that
was seen as a necessity -- but I'd still lean toward it not being noticable.

-l 

--
Linda A Walsh                    | Trust Technology, Core Linux, SGI
law@sgi.com                      | Voice: (650) 933-5338                        

> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org
> [mailto:linux-kernel-owner@vger.kernel.org]On Behalf Of Richard
> Henderson
> Sent: Thursday, August 31, 2000 9:51 PM
> To: Matti Aarnio
> Cc: Linda Walsh; lkml
> Subject: Re: Large File support and blocks.
> 
> 
> On Fri, Sep 01, 2000 at 12:16:38AM +0300, Matti Aarnio wrote:
> > 	Also (I recall) because GCC's 'long long' related operations
> > 	and optimizations have been buggy in past, and there is no
> > 	sufficient experience to convince him that they work now better
> > 	with the recommended kernel compiling GCC version (egcs-1.1.2).
> 
> To my knowlege it's only been speed related issues, not
> correctness issues, that have been the cause for the
> fear and loathing of long long.
> 
> 
> r~
> -
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