Hello,

CR 6248065 is quite interesting. However, some reasons from 2005 aren't 
much applicable nowadays (system is more-or-less 64-bit-proof now).
And well, maybe it's not about optimization, it's more about policy for 
using isa directories.

SDL case is absolutely unclear: if one knows which ISA to use, he 
doesn't need to call specific sdl-config, but rather can manually use 
appropriate dirs in -L flag; if one doesn't know which ISA to use, 
presence of many versions of sdl-config wouldn't help.


Milan Jurik wrote:
> Hi,
>
> V po, 09. 02. 2009 v 16:05, [email protected] píše:
>   
>>> However, in OpenSolaris I can see few deviations from this principle: 
>>> /usr/bin/amd64 contains more binaries than /usr/bin/i86 and 
>>> /usr/bin/pentium_pro+mmx together; for example, take a look at `ls' or 
>>> `sdl-config':
>>>
>>> /usr/bin/amd64/ls is 64-bit binary
>>> /usr/bin/i86/ls is not present
>>> /usr/bin/pentium_pro+mmx/ls is not present
>>> /usr/bin/ls is 32-bit binary of ls, not a link to isaexec
>>>
>>> so when user types `ls', 32-bit version of ls is always being called, 
>>> regardless of  architecture. 64-bit version is being useless unless 
>>> called directly as /usr/bin/amd64/ls.
>>> If someone intended to use optimized version of ls, he had to ship 
>>> 32-bit binary in /usr/bin/i86 and made /usr/bin/ls a link to isaexec
>>>       
>> I think the reason was "optimization": make "ls" fast and save an execve.
>>
>>     
>
> See some bits in CR 6248065. It is not about optimization so much.
>
>   
>>> Now take a look at sdl-config: it's a shell script which outputs flags 
>>> for compiling application using SDL library.
>>>
>>> /usr/bin/amd64/sdl-config is a script which outputs flags for 64-bit library
>>> /usr/bin/pentium_pro+mmx/sdl-config is a script which outputs flags for 
>>> 32-bit library, SSE, SSE2, CMOV enabled
>>> /usr/bin/sdl-config is a script which outputs flags for generic 32-bit 
>>> library
>>>
>>> so calling sdl-config will always print flags for most generic 32-bit 
>>> version, ignoring more optimized ones.
>>>       
>> I have no idea about sdl-config.
>>
>>     
>
> Interesting usage, which has it points, but no idea why it was done in
> this way. SDL maintainer should know.
>
> Best regards,
>
> Milan
>
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>   
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