AMD Sempron CPUTYPE & Co.

jason jason at ec.rr.com
Thu Sep 22 19:28:31 PDT 2005


Andrew P. wrote:

>On 9/22/05, jason <jason at ec.rr.com> wrote:
>  
>
>>Andrew P. wrote:
>>
>>    
>>
>>>Hello!
>>>
>>>So I have a Sempron 2500+ CPU, one that supports
>>>SSE3. What should I place in my /etc/make.conf? I use
>>>ssh with X11Forward very often, so OpenSSL should
>>>be compiled to be as fast as it can be on this CPU.
>>>Here's a part of dmesg:
>>>
>>>CPU: AMD Sempron(tm) Processor 2500+
>>>(1407.05-MHz 686-class CPU)
>>>Origin = "AuthenticAMD"  Id = 0x20fc2  Stepping = 2
>>>
>>> Features=0x78bfbff<FPU,VME,DE,PSE,TSC,MSR,
>>>PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,
>>>PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2>
>>> Features2=0x1<SSE3>
>>> AMD Features=0xe2500800<SYSCALL,NX,MMX+,
>>><b25>,LM,3DNow+,3DNow>
>>>
>>>I want to use SSE3, but I don't want to set CPUTYPE
>>>to nocona, cause that way compilers won't ever use
>>>AMD features. Is there a way to tell compilers to use
>>>every feature I've got?
>>>
>>>
>>>Thanks very much,
>>>Andrew P.
>>>_______________________________________________
>>>freebsd-questions at freebsd.org mailing list
>>>http://lists.freebsd.org/mailman/listinfo/freebsd-questions
>>>To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"
>>>
>>>
>>>
>>>      
>>>
>>man make.conf and man gcc
>>
>>You will be limited by the gcc version on FreeBSD.  You can use gcc 4
>>for your apps, and all that SSE and 3DNow  stuff is not currently
>>allowed in the kernel.
>>
>>I remember ready, maybe on slashdot, where a man did very little work to
>>do a native port of ssh to native amd64 code and got a hugh speed
>>boost.  Making sure you get a optimized version os ssh like what I
>>described will make a much bigger difference than just adding amd64 as
>>your cp type to make.conf.
>>
>>Jason
>>    
>>
>
>I run FreeBSD/i386, not amd64.
>
>make.conf, gcc and cpp manpages tell you nothing about
>the subj. I roamed mailing lists for a few hours and settled on
>adding "-march=pentium4 -msse3" to CFLAGS and COPTFLAGS.
>I didn't do any serious benchmarking, but the `top` output feels
>like sshd got 2-3% performance boost. Will try to recompile
>with "-mfpmath=sse" later.
>
>Also, I tried forwarding X11 over network without SSH, and
>some things kept lagging. My guess is network connection
>and my solution is a Gigabit switch; the funny thing is that
>I have Gb NICs in most of my PCs, but I still use a 100Mb
>switch.
>
>  
>
Hmm, that sucks.  The K8 core in 32bit mode.  I have heard of native 32 
bit semprons, is that what you have?

Well check this man page
http://gcc.gnu.org/onlinedocs/gcc-3.4.4/gcc/i386-and-x86_002d64-Options.html#i386-and-x86_002d64-Options

it will have everything, I hope, you need to know.


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