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SilveRo
Tux's lil' helper
Joined: 13 Oct 2003
Posts: 147
Location: Milan (Italy)
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 Posted: Wed Jun 23, 2004 1:05 pm Post subject: Centrino && SSE* => risky?? |
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Hi =)
Some time ago I got a new Centrino laptop (Dell I8600), and I searched the forums for info about what CFLAGS to use.
Many users said not to use SSE or SSE2, even though the Pentium-M supports them, because of instability issues. So I left them out....
My system runs perfectly. It's stable and very fast: it emerged everything and I configured everything in less than 24 hours (setting an alarm clock to go off every hour at night and making my girlfriend mad).
My questions:
1) is it safe to add SSE and SSE2? (I'd also like reports from Centrino owners that are using them)
2) if I add them, and I do 'emerge world', will it recompile everything, or is there a (maybe better) way to do this?
3) are these flags I have been using so far ok?
| Code: | CFLAGS="-O3 -march=pentium3 -fomit-frame-pointer -funroll-all-loops -ftracer -momit-leaf-frame-pointer -pipe"
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4) is it worth waiting for the GCC release that supports explicitly the "pentium-m"? (it's supposed to be released at some time)
THX =)
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Voltago
Advocate
Joined: 02 Sep 2003
Posts: 2593
Location: userland
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| Posted: Wed Jun 23, 2004 1:17 pm Post subject: |
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| You are using SSE anyway, because -march=pentium3 implies -msse. |
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SilveRo
Tux's lil' helper
Joined: 13 Oct 2003
Posts: 147
Location: Milan (Italy)
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| Posted: Wed Jun 23, 2004 1:42 pm Post subject: |
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| Voltago wrote: | | You are using SSE anyway, because -march=pentium3 implies -msse. |
Is that right? man, I had no idea.... thx =)
And what about SSE2?
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xces
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Joined: 11 Oct 2002
Posts: 515
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| Posted: Wed Jun 23, 2004 3:43 pm Post subject: |
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| SilveRo wrote: | | And what about SSE2? |
-msse2 is not implied by -march=pentium3. You can just add it to your CFLAGS.
If you use gcc 3.4.0 you should choose -march=pentium-m which implies -msse, -msse2 and -mmmx. |
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SilveRo
Tux's lil' helper
Joined: 13 Oct 2003
Posts: 147
Location: Milan (Italy)
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| Posted: Wed Jun 23, 2004 5:29 pm Post subject: |
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| xces wrote: | | SilveRo wrote: | | And what about SSE2? |
-msse2 is not implied by -march=pentium3. You can just add it to your CFLAGS.
If you use gcc 3.4.0 you should choose -march=pentium-m which implies -msse, -msse2 and -mmmx. |
THX =)
Uhm, nope, gcc 3.4 is not available for x86 yet, and I'm not sure if I should use it before it goes stable.
I am considering adding sse2, but can anyone tell me if it's worth it and if it's safe with a Centrino?
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xces
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Joined: 11 Oct 2002
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| Posted: Wed Jun 23, 2004 6:28 pm Post subject: |
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| I have (well, had until I switched to gcc 3.4.0) the CFLAG -msse2. Everything worked. Was it worth it? I don't know, really. Never did any benchmarks. |
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SilveRo
Tux's lil' helper
Joined: 13 Oct 2003
Posts: 147
Location: Milan (Italy)
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| Posted: Wed Jun 23, 2004 6:43 pm Post subject: |
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| xces wrote: | | I have (well, had until I switched to gcc 3.4.0) the CFLAG -msse2. Everything worked. Was it worth it? I don't know, really. Never did any benchmarks. |
OK, I'll try to make my mind up =)
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