Some Thoughts on the Current State of 64-bit Computing [LWN.net]

Some Thoughts on the Current State of 64-bit Computing

Posted Feb 17, 2005 16:40 UTC (Thu) by elanthis (guest, #6227)
In reply to: Some Thoughts on the Current State of 64-bit Computing by Duncan
Parent article: Some Thoughts on the Current State of 64-bit Computing

"How many people are
running x86 binary platforms (libre or not) optimized for the lowest
common denominator, i386, i586, i686 if one is lucky, because it's not so
practical to deliver all those options and more (latest SSE optimized,
etc) in a multitude of binary packages?"

Fortunately, it doesn't matter if you compile for i386 or not, because almost every piece of software that needs SSE or the like does the detection at *run-time*. Simply compiling for a newer version of an architecture isn't going to make your apps run any faster; heck, depending on exactly what the app does and which compiler you use, it might even end up slower. You can't automatically turn some random bit of code into an SSE-using speed demon.

For the few apps and libs were the recompilation *can* make a difference, at least some "lowest common denominator" distros provide multiple architectures of those packages, Debian and Fedora included.

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Fedora and optimisation Current State of 64-bit Computing

Posted Feb 18, 2005 3:01 UTC (Fri) by gdt (subscriber, #6284) [Link]

Although FC3 contains "i386" packages which only use 80386 instructions the choice and order of those instructions is optimised for the Pentium 4.

The problem with the tactic of providing i686 versions of packages is that the demonimation no longer discriminates between the processor classes of interest: Pentium II, Pentium III/Pentium M and Pentium 4.

The tactic also fails for machines with a targetted use. It might be acceptable not to get the utmost out of Apache or Samba when they are used on a desktop, but it is not so acceptable when Apache is used as a web server or Samba is used as a file server.

Some Thoughts on theCurrent State of 64-bit Computing

Posted Feb 18, 2005 7:36 UTC (Fri) by nix (subscriber, #2304) [Link]

You can't automatically turn some random bit of code into an SSE-using speed demon.

-mfpmath=sse? :)

(Of course, this breaks the i386 ABI, so is really an argument in favour of your point...)