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MindFlayer n00b
Joined: 26 Jun 2002 Posts: 4
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Posted: Tue Jan 14, 2003 2:46 pm Post subject: march=Athlon on a Duron? |
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My cpu is (supposedly) a 700 Mhz Duron. Lastnight while I was reinstalling Gentoo on my system I decided to do some optimization. As part of that I did 'march=duron -03 -pipe' ...and nothing would compile. So I tried mcpu=duron, same thing. Being in a mood to play around I then tried 'march=athlon -03 -pipe' and to my great surprise everything compiled flawlessly.
Now, correct me if I'm wrong, but does that not infer that my cpu is in reality an athlon? Since 'march=foobar' should cause it to ONLY work with cpu's of type 'foobar' with no backward compatability, correct? |
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bpkri Tux's lil' helper
Joined: 07 Aug 2002 Posts: 118 Location: Germany
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Posted: Tue Jan 14, 2003 2:52 pm Post subject: |
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There is no specific target called "duron" for gcc 3.2.x
-mcpu=cpu-type
Tune to cpu-type everything applicable about the generated code, except for the ABI and the set of available instructions. The choices for cpu-type are i386, i486, i586, i686, pentium, pentium-mmx, pentiumpro, pentium2, pentium3, pentium4, k6, k6-2, k6-3, athlon, athlon-tbird, athlon-4, athlon-xp and athlon-mp. While picking a specific cpu-type will schedule things appropriately for that particular chip, the compiler will not generate any code that does not run on the i386 without the -march=cpu-type option being used. i586 is equivalent to pentium and i686 is equivalent to pentiumpro. k6 and athlon are the AMD chips as opposed to the Intel ones.
-march=cpu-type
Generate instructions for the machine type cpu-type. The choices for cpu-type are the same as for -mcpu. Moreover, specifying -march=cpu-type implies -mcpu=cpu-type.
Find this at http://gcc.gnu.org/onlinedocs/gcc-3.2.1/gcc/i386-and-x86-64-Options.html#i386%20and%20x86-64%20Options |
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MindFlayer n00b
Joined: 26 Jun 2002 Posts: 4
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Posted: Tue Jan 14, 2003 3:02 pm Post subject: |
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Ok, thanks for the clarification and info. The comments section of my /etc/make.conf file said that 'duron' was an option for gcc 3.2.x but not for gcc 2.9.x. |
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bpkri Tux's lil' helper
Joined: 07 Aug 2002 Posts: 118 Location: Germany
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Posted: Tue Jan 14, 2003 3:29 pm Post subject: |
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Umm - if this is really in the comments of /etc/make.conf it is a obviously wrong... |
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wrc1944 Advocate
Joined: 15 Aug 2002 Posts: 3435 Location: Gainesville, Florida
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Posted: Tue Jan 14, 2003 7:34 pm Post subject: |
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MindFlayer,
It's my understanding that Durons 900mhz or below are actually equivalent to Athlon T-birds (just less cache on the chip), and use the same compiler optimizations. The "athlon" specification is for the original older Athlon chips.
Likewise, the newer Durons, 1.2mhz.1.3mhz, are the same as the Athlon XP series chips, again, just less cache.
wrc1944 _________________ Main box- AsRock x370 Gaming K4
Ryzen 7 3700x, 3.6GHz, 16GB GSkill Flare DDR4 3200mhz
Samsung SATA 1000GB, Radeon HD R7 350 2GB DDR5
OpenRC Gentoo ~amd64 plasma, glibc-2.36-r7, gcc-13.2.1_p20230304
kernel-6.8.4 USE=experimental python3_11 |
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sOuLjA Guru
Joined: 26 Jul 2002 Posts: 366 Location: germany - hannover
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Posted: Tue Jan 14, 2003 7:37 pm Post subject: |
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I have a duron 800 and I use "-march=athlon ...." and it works without problems _________________ Gentoo Linux / gentoo-sources 2.6.28-r1 / fluxbox 1.1.1
Nexoc Osiris S602 / Pentium M 1,4GHZ / 1024 MB RAM / Intel 855GME 64 MB
www.gentooforum.de |
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wrc1944 Advocate
Joined: 15 Aug 2002 Posts: 3435 Location: Gainesville, Florida
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Posted: Wed Jan 15, 2003 8:50 pm Post subject: |
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I'm not saying it won't work, as it will also work with i686 or below optimizations. I'm just saying that the first durons are actually Athlon t-birds with a smaller cache- they are in fact based on exactly the same architecture, thus will accept the t-bird opts. The newer 1.3GB durons are supposedly of the Athlon XP architecture.
If I'm not mistaken, the plain "athlon" optimizations are specifically meant for the older slot type original Athlon chips. I suppose it would be better than i686, but not as good as t-bird opts. This is assuming, of course, that any of this really makes any difference in real world applications. I'd like to see some serious benchmark comparisons before I'm convinced one way or the other- the fact is, I don't really know, and lacking any evidence based on that, it's just subjective judgments about "speed," "feel," or "performance." That said, I'm all for great performance, and if it seems "faster," of course I'll go for it big time.
wrc1944 _________________ Main box- AsRock x370 Gaming K4
Ryzen 7 3700x, 3.6GHz, 16GB GSkill Flare DDR4 3200mhz
Samsung SATA 1000GB, Radeon HD R7 350 2GB DDR5
OpenRC Gentoo ~amd64 plasma, glibc-2.36-r7, gcc-13.2.1_p20230304
kernel-6.8.4 USE=experimental python3_11 |
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