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On Sun, 2008-04-20 at 13:39 -0400, Allan Gottlieb wrote: |
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> I have an intel core2 duo (currently in 32 bit mode x86). |
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> Is there any reason why I should not set the following use flags. |
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> |
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> mmx, sse, sse2, ssse3 |
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> |
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> The last one would be a local flag for mplayer. |
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> |
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> proc/cpu indicates I have this functionality. |
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> |
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> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov |
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> pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm |
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> constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 |
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> ssse3 cx16 xtpr lahf_lm |
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> |
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> thanks, |
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> allan |
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|
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As a use flag, you should set all you can. They all enable the use of |
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optimized code and the code I've seen from this was clever enough to |
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choose the best if several were available. |
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|
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Please don't confuse this with the CFLAGS in your make.conf, there you |
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should only choose the latest and this should be automatically applied |
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by march=nocona (one exception are newer Athlons, because |
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march=k8/athlon64/opteron/athlon-fx only activates SSE2 but not SSE3). |
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By the way: Does anyone know why mmx2 (or was it mmxext?) isn't listed |
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in cpuinfo for Core2 processors? Since it's a subset of SSE it should |
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really be there, right? |
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