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DaNe
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Joined: 29 Apr 2006
Posts: 192
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 Posted: Wed Jan 30, 2008 6:40 pm Post subject: [SOLVED] same kernel for different cpus |
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i'm configuring a kernel for 3 types of computers almost all AMD(the others p3),
the question is i should select in the Processor family: Athlon/Duron/K7, or something more general like 586?
AFAIK the processor family is only for optimization or it limits the hardware that kernel accept?
ps:
i have to
[*] Generic x86 support
Last edited by DaNe on Thu Jan 31, 2008 4:17 pm; edited 1 time in total |
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ragefan
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Joined: 01 Jun 2002
Posts: 63
Location: Roanoke, Virginia, USA
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| Posted: Wed Jan 30, 2008 7:01 pm Post subject: |
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I think you want i686 not 586.
-march=i686 will work for both Intel P3 and beyond as well as Athlon K7 and beyond
Edited for typo, thanks andreas_st.
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Last edited by ragefan on Wed Jan 30, 2008 7:50 pm; edited 1 time in total |
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andreas_st
Tux's lil' helper
Joined: 26 Dec 2007
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Location: 48N 16E
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| Posted: Wed Jan 30, 2008 7:20 pm Post subject: |
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| ragefan wrote: | I think you want i686 not 586.
-march=i686 will work for both Intel P3 and beyond as well as Athlon K6 and beyond |
Probably this is just a typo but to be sure: there is no Athlon K6. AMD K6-II and K6-III are i586. Athlon started with K7. |
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DaNe
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Joined: 29 Apr 2006
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| Posted: Wed Jan 30, 2008 9:25 pm Post subject: |
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I'm talking about the Kernel not the flags.
you don't answered my question:changing the processor family in the kernel config limits my options?
the thing is i dont see any 686 in kernel? only M586 that in menu is 586/k5/5x86/6x86/6x86MX |
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Carnildo
Guru
Joined: 17 Jun 2004
Posts: 595
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| Posted: Wed Jan 30, 2008 10:46 pm Post subject: Re: same kernel for different cpus |
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| DaNe wrote: | i'm configuring a kernel for 3 types of computers almost all AMD(the others p3),
the question is i should select in the Processor family: Athlon/Duron/K7, or something more general like 586? |
What exact CPUs are you trying to support? |
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DaNe
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Joined: 29 Apr 2006
Posts: 192
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| Posted: Wed Jan 30, 2008 11:28 pm Post subject: |
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bad luck
i turned almost all pcs off
23: AMD Sempron(tm) 2400 (these are on so i cant get the specs)
Im almost sure that the others are:
8: p3
10: amd sempron
8: amd xp
anyway i think more specification wouldn't be more helpfull
ps: the first 23 and the last 18 are running with CONFIG_MK7(if it helps)
if you want to help me with flags fine 
(i was thinking:
-O2 -march=i686 -mno-tls-direct-seg-refs -pipe (this are the ones that are running right now))
the my main question is the processor family limits where kernel could run? its like the march in the flags?(if I specify for example pentium3 in the flags mine amd will not run) |
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Carnildo
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Joined: 17 Jun 2004
Posts: 595
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| Posted: Thu Jan 31, 2008 12:14 am Post subject: |
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| Generic x86 support with a "586" processor family should give you a kernel that works well on all of them: the Athlon XP and Sempron both support everything the Pentium III does, and have similar optimization rules. You might not even need generic x86 support. |
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DaNe
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Joined: 29 Apr 2006
Posts: 192
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| Posted: Thu Jan 31, 2008 12:55 am Post subject: |
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thanks for the help
but why not the 686?
ps: i found it is in Pentium Pro
| Code: |
CONFIG_M686: │
│ │
│ Select this for Intel Pentium Pro chips. This enables the use of │
│ Pentium Pro extended instructions, and disables the init-time guard │
│ against the f00f bug found in earlier Pentiums. │
│ │
│ Symbol: M686 [=n] │
│ Prompt: Pentium-Pro
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but explain me a thing by selecting the processor family without the x86 there's a chance to things dont work or the processor family its just a optimization?
like if i select pentium 4 the kernel would run great on a p4 but runs anyway in a p3 but with less performance?
sorry but I'm really trying to understand this |
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Carnildo
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Joined: 17 Jun 2004
Posts: 595
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| Posted: Thu Jan 31, 2008 3:25 am Post subject: |
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| DaNe wrote: | thanks for the help
but why not the 686? |
686 should also work -- I'd forgotten that the PIII was a 686.
| Quote: | but explain me a thing by selecting the processor family without the x86 there's a chance to things dont work or the processor family its just a optimization?
like if i select pentium 4 the kernel would run great on a p4 but runs anyway in a p3 but with less performance? |
By selecting a family but not selecting generic support, you create a kernel that will run on that processor family and everything newer, but which won't run on anything older. Selecting a processor family also determines which optimization rules the compiler will use. The Pentium 4 has a very different internal architecture than the Pentium III: a program optimized for the PIII will run slowly on a P4, and vice versa. The AMD chips are more similar to a PIII than to a P4, so using the PIII rules will give a kernel that's fairly fast on them as well.
Looking at the available options, you'll certainly be able to use the "Pentium Pro" option, and you might be able to use "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon" -- I think the Athlon XP supports everything the PIII does. Experiment a bit -- it's usually instantly obvious when a kernel can't work with a given processor. |
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DaNe
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Joined: 29 Apr 2006
Posts: 192
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| Posted: Thu Jan 31, 2008 4:17 pm Post subject: |
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now i understanded
tks a lot |
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