By: agony (no.delete@this.spam.com), November 14, 2006 2:57 pm
Room: Moderated Discussions
Rob Thorpe (rthorpe@realworldtech.com) on 11/14/06 wrote:
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>Apart from geeks I've met very few people who have any legacy software at all on
>their machines. Most users use the software that is installed on the system when
>they bought it, only occasionally buying new packages. When they buy a new machine
>they start again, getting a new version of Windows, Office etc.
Depends on how you define legacy software. In my point of view, almost every piece of software I have in my computer are legacy because they are compiled with 32 bit and x87 math while my computer can do 64 bit and SSE2 math. And I do care about the performance. My computer does run the legacy software well; taking maybe 20% speed hit at most. I think this is the point Linus is trying to make: You have to be able to run legacy software well; at least not slower that your previous generation cpu.
>There aren't really many problems. The things we're talking about rarely affect
>code in a very major way as it is. For years x86 Linux distributions used code
>compiled for the P5, which performs poorly on the P6s most people were actually
>using. In practice very few people complained or even noticed. Similarly x87 performance
>has been sacrificed recently in aid of SSE even though few old programs (and few
>programs in general) use SSE. No-one is complaining about this or arguing that it is bad.
If Intel made a cpu that use software trap to emulate X87 math and told everybody who care about performance to "simply recompile" with SSE math, I am sure as hell that people would switch to AMD in droves.
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>Apart from geeks I've met very few people who have any legacy software at all on
>their machines. Most users use the software that is installed on the system when
>they bought it, only occasionally buying new packages. When they buy a new machine
>they start again, getting a new version of Windows, Office etc.
Depends on how you define legacy software. In my point of view, almost every piece of software I have in my computer are legacy because they are compiled with 32 bit and x87 math while my computer can do 64 bit and SSE2 math. And I do care about the performance. My computer does run the legacy software well; taking maybe 20% speed hit at most. I think this is the point Linus is trying to make: You have to be able to run legacy software well; at least not slower that your previous generation cpu.
>There aren't really many problems. The things we're talking about rarely affect
>code in a very major way as it is. For years x86 Linux distributions used code
>compiled for the P5, which performs poorly on the P6s most people were actually
>using. In practice very few people complained or even noticed. Similarly x87 performance
>has been sacrificed recently in aid of SSE even though few old programs (and few
>programs in general) use SSE. No-one is complaining about this or arguing that it is bad.
If Intel made a cpu that use software trap to emulate X87 math and told everybody who care about performance to "simply recompile" with SSE math, I am sure as hell that people would switch to AMD in droves.
