Linux-kernel mailing list archive 1998-31,: Re: CyrixInstead ?

# Re: CyrixInstead ?

Nicolai P Guba (nicolai@jungle.BT.co.uk)
03 Aug 1998 09:39:37 +0100

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"ADB" == Andrew Derrick Balsa <andrebalsa@altern.org> writes:

ADB> Hello Nicolai,
Hi

>> Hmmm, I've gotten a Cyrix 6x86 (IBM actually) and compiled kernels as
>> Pentium/6x86 and never got my CPU identified correctly (unknown).

ADB> On 2.1.112 you can compile your kernel as a 386, 486, 586 or 686 and
ADB> you will still get correct identification of your Cyrix 6x86.
>> Now I compiled (2.1.112) as 486 and voila,

ADB> Hmmm, you were probably using an older kernel previously. Note that the
ADB> recommended setting for the 6x86 is to compile as a Pentium, PPro or as
ADB> a last resort, as a 386. Compiling as a 486 diminishes kernel
ADB> performance because of the extra padding needed on 486-class CPUs.
I know that. But I had tried it to see whether the kernels detected the 6x86
cpu's if I compiled them as a lower spec. There was absolutely no chance
getting the cpu detected when compiled as Pentium --which is why I send the
message in the first place.

ADB> Looks OK to me. :-)
That was the correct output. The other junst says unknown.

ADB> This is the desired behaviour and the 6x86 is a Pentium class
ADB> processor. In fact at the same clock rate it provides roughly 10%
ADB> better kernel performance than a Pentium. Your 133MHz 6x86 is roughly
ADB> equivalent to a 150MHz Pentium, in terms of kernel performance.
I believe that my output has confused you.

ADB> Please compile your 2.1.112 kernel as a Pentium processor and you will
ADB> notice the CPU is (correctly) identified as above. There is no need to
ADB> compile as a 486 (and it is not desirable either); the menuconfig and
ADB> xconfig information is correct.
Nope, I wasn't. That was precisely my point ;)

    --
    Nicolai P Guba, BSc(Hons)		BT Networks and Systems
    Managerial Professional Grade		Applied Research and Technology
    BT Research Laboratories		Distributed Systems Group
    Martlesham Heath, Suffolk IP5 3RE	pp B54/R73

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