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-   -   Increasing minimum 'i386' processor (http://www.linux-archive.org/debian-kernel/600369-increasing-minimum-i386-processor.html)

Ben Hutchings 11-19-2011 09:42 PM

Increasing minimum 'i386' processor
 
The i386 architecture was the first in Linux and in Debian, but we have
long since dropped support for the original i386-compatible processors
and now require a minimum of a 486-class processor.

I think it is time to increase the minimum requirement to 586-class, if
not for wheezy then immediately after. (Later it should be increased
further, and eventually i386 should be reduced to a partial architecture
that may be installed on amd64 systems.) This would allow the use of
optimisations and new instructions throughout userland that improve
performance for the vast majority of users.

The 486-class processors that would no longer be supported are:
1. All x86 processors with names including '486'
2. AMD Am5x86
3. Cyrix/IBM/ST 5x86, 6x86 and MediaGX
4. UMC U5D and U5S
5. AMD/NSC Geode GX1, Geode SC1100, Elan SC4xx and SC5xx
Also possibly:
6. DM&P/SiS Vortex86 and Vortex86SX. These supposedly have all
586-class features except an FPU, and we could probably keep FPU
emulation for them.

So far as I know, all processors in groups 1-5 have been out of
production for several years. Soekris still advertises boards using the
Geode SC1100 and Elan SC520, but they seem quite uncompetitive with
ARM-based systems and at least the SC1100-based products are being
EOL'd.

Starting from version 2.6.24 or earlier (early 2008), Debian '486'
kernel packages had a bug that caused them to crash on boot on 486-class
processors, but this was not reported until early 2009 (#511703),
suggesting that there were few users with such systems. Debian 7.0
'wheezy' should be released in late 2012 or early 2013 and in the
intervening 4 years the numbers of running systems with such a processor
will have declined still further.

Ben.

--
Ben Hutchings
The world is coming to an end. Please log off.

Ben Hutchings 11-19-2011 09:42 PM

Increasing minimum 'i386' processor
 
The i386 architecture was the first in Linux and in Debian, but we have
long since dropped support for the original i386-compatible processors
and now require a minimum of a 486-class processor.

I think it is time to increase the minimum requirement to 586-class, if
not for wheezy then immediately after. (Later it should be increased
further, and eventually i386 should be reduced to a partial architecture
that may be installed on amd64 systems.) This would allow the use of
optimisations and new instructions throughout userland that improve
performance for the vast majority of users.

The 486-class processors that would no longer be supported are:
1. All x86 processors with names including '486'
2. AMD Am5x86
3. Cyrix/IBM/ST 5x86, 6x86 and MediaGX
4. UMC U5D and U5S
5. AMD/NSC Geode GX1, Geode SC1100, Elan SC4xx and SC5xx
Also possibly:
6. DM&P/SiS Vortex86 and Vortex86SX. These supposedly have all
586-class features except an FPU, and we could probably keep FPU
emulation for them.

So far as I know, all processors in groups 1-5 have been out of
production for several years. Soekris still advertises boards using the
Geode SC1100 and Elan SC520, but they seem quite uncompetitive with
ARM-based systems and at least the SC1100-based products are being
EOL'd.

Starting from version 2.6.24 or earlier (early 2008), Debian '486'
kernel packages had a bug that caused them to crash on boot on 486-class
processors, but this was not reported until early 2009 (#511703),
suggesting that there were few users with such systems. Debian 7.0
'wheezy' should be released in late 2012 or early 2013 and in the
intervening 4 years the numbers of running systems with such a processor
will have declined still further.

Ben.

--
Ben Hutchings
The world is coming to an end. Please log off.

Ben Hutchings 11-19-2011 09:42 PM

Increasing minimum 'i386' processor
 
The i386 architecture was the first in Linux and in Debian, but we have
long since dropped support for the original i386-compatible processors
and now require a minimum of a 486-class processor.

I think it is time to increase the minimum requirement to 586-class, if
not for wheezy then immediately after. (Later it should be increased
further, and eventually i386 should be reduced to a partial architecture
that may be installed on amd64 systems.) This would allow the use of
optimisations and new instructions throughout userland that improve
performance for the vast majority of users.

The 486-class processors that would no longer be supported are:
1. All x86 processors with names including '486'
2. AMD Am5x86
3. Cyrix/IBM/ST 5x86, 6x86 and MediaGX
4. UMC U5D and U5S
5. AMD/NSC Geode GX1, Geode SC1100, Elan SC4xx and SC5xx
Also possibly:
6. DM&P/SiS Vortex86 and Vortex86SX. These supposedly have all
586-class features except an FPU, and we could probably keep FPU
emulation for them.

So far as I know, all processors in groups 1-5 have been out of
production for several years. Soekris still advertises boards using the
Geode SC1100 and Elan SC520, but they seem quite uncompetitive with
ARM-based systems and at least the SC1100-based products are being
EOL'd.

Starting from version 2.6.24 or earlier (early 2008), Debian '486'
kernel packages had a bug that caused them to crash on boot on 486-class
processors, but this was not reported until early 2009 (#511703),
suggesting that there were few users with such systems. Debian 7.0
'wheezy' should be released in late 2012 or early 2013 and in the
intervening 4 years the numbers of running systems with such a processor
will have declined still further.

Ben.

--
Ben Hutchings
The world is coming to an end. Please log off.

Timo Juhani Lindfors 11-19-2011 09:55 PM

Increasing minimum 'i386' processor
 
Ben Hutchings <ben@decadent.org.uk> writes:
> 5. AMD/NSC Geode GX1, Geode SC1100, Elan SC4xx and SC5xx

Does this mean that "AMD Geode LX" as mentioned in
http://pcengines.ch/alix.htm still works?

damager:~$ cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 5
model : 10
model name : Geode(TM) Integrated Processor by AMD PCS
stepping : 2
cpu MHz : 498.026
cache size : 128 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu de pse tsc msr cx8 sep pge cmov clflush mmx mmxext 3dnowext 3dnow up
bogomips : 996.05
clflush size : 32
cache_alignment : 32
address sizes : 32 bits physical, 32 bits virtual
power management:


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Ben Hutchings 11-19-2011 10:29 PM

Increasing minimum 'i386' processor
 
On Sun, 2011-11-20 at 00:55 +0200, Timo Juhani Lindfors wrote:
> Ben Hutchings <ben@decadent.org.uk> writes:
> > 5. AMD/NSC Geode GX1, Geode SC1100, Elan SC4xx and SC5xx
>
> Does this mean that "AMD Geode LX" as mentioned in
> http://pcengines.ch/alix.htm still works?
[...]

Yes, the later 'Geode' processors are 686-class.

Ben.

--
Ben Hutchings
The world is coming to an end. Please log off.

Guillem Jover 11-19-2011 11:08 PM

Increasing minimum 'i386' processor
 
Hi!

On Sat, 2011-11-19 at 22:42:11 +0000, Ben Hutchings wrote:
> The i386 architecture was the first in Linux and in Debian, but we have
> long since dropped support for the original i386-compatible processors
> and now require a minimum of a 486-class processor.
>
> I think it is time to increase the minimum requirement to 586-class, if
> not for wheezy then immediately after. (Later it should be increased
> further, and eventually i386 should be reduced to a partial architecture
> that may be installed on amd64 systems.) This would allow the use of
> optimisations and new instructions throughout userland that improve
> performance for the vast majority of users.

It seems gcc has been targetting i586 instruction set by default since
gcc 4.4.0-1~exp1, although the triplet was not changed to match. On the
discussion regarding multiarch tuples I proposed we should switch the
triplet back to i386-linux-gnu to avoid this kind of confusion, fix the
internal inconsistency and the one with other architectures (which do
not track the base instruction set in the triplet) and so that we can
use them directly as the multiarch tuples.

For more details please see:

<http://lists.debian.org/debian-dpkg/2011/02/msg00061.html>
<http://lists.debian.org/debian-dpkg/2011/02/msg00039.html>

regards,
guillem


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Guillem Jover 11-19-2011 11:08 PM

Increasing minimum 'i386' processor
 
Hi!

On Sat, 2011-11-19 at 22:42:11 +0000, Ben Hutchings wrote:
> The i386 architecture was the first in Linux and in Debian, but we have
> long since dropped support for the original i386-compatible processors
> and now require a minimum of a 486-class processor.
>
> I think it is time to increase the minimum requirement to 586-class, if
> not for wheezy then immediately after. (Later it should be increased
> further, and eventually i386 should be reduced to a partial architecture
> that may be installed on amd64 systems.) This would allow the use of
> optimisations and new instructions throughout userland that improve
> performance for the vast majority of users.

It seems gcc has been targetting i586 instruction set by default since
gcc 4.4.0-1~exp1, although the triplet was not changed to match. On the
discussion regarding multiarch tuples I proposed we should switch the
triplet back to i386-linux-gnu to avoid this kind of confusion, fix the
internal inconsistency and the one with other architectures (which do
not track the base instruction set in the triplet) and so that we can
use them directly as the multiarch tuples.

For more details please see:

<http://lists.debian.org/debian-dpkg/2011/02/msg00061.html>
<http://lists.debian.org/debian-dpkg/2011/02/msg00039.html>

regards,
guillem


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Guillem Jover 11-19-2011 11:08 PM

Increasing minimum 'i386' processor
 
Hi!

On Sat, 2011-11-19 at 22:42:11 +0000, Ben Hutchings wrote:
> The i386 architecture was the first in Linux and in Debian, but we have
> long since dropped support for the original i386-compatible processors
> and now require a minimum of a 486-class processor.
>
> I think it is time to increase the minimum requirement to 586-class, if
> not for wheezy then immediately after. (Later it should be increased
> further, and eventually i386 should be reduced to a partial architecture
> that may be installed on amd64 systems.) This would allow the use of
> optimisations and new instructions throughout userland that improve
> performance for the vast majority of users.

It seems gcc has been targetting i586 instruction set by default since
gcc 4.4.0-1~exp1, although the triplet was not changed to match. On the
discussion regarding multiarch tuples I proposed we should switch the
triplet back to i386-linux-gnu to avoid this kind of confusion, fix the
internal inconsistency and the one with other architectures (which do
not track the base instruction set in the triplet) and so that we can
use them directly as the multiarch tuples.

For more details please see:

<http://lists.debian.org/debian-dpkg/2011/02/msg00061.html>
<http://lists.debian.org/debian-dpkg/2011/02/msg00039.html>

regards,
guillem


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Raphael Hertzog 11-20-2011 06:40 AM

Increasing minimum 'i386' processor
 
On Sat, 19 Nov 2011, Ben Hutchings wrote:
> Also possibly:
> 6. DM&P/SiS Vortex86 and Vortex86SX. These supposedly have all
> 586-class features except an FPU, and we could probably keep FPU
> emulation for them.

FWIW, I do run Debian on such systems albeit with a custom kernel.
Given those CPU tend to be used in an "embedded" context I guess
it's ok if the official kernel does not support them. But it would be
nice if Debian's userspace could be kept compatible. Not sure what this
requires though...

Cheers,
--
Raphaël Hertzog ◈ Debian Developer

Pre-order a copy of the Debian Administrator's Handbook and help
liberate it: http://debian-handbook.info/go/ulule-rh/


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Raphael Hertzog 11-20-2011 06:40 AM

Increasing minimum 'i386' processor
 
On Sat, 19 Nov 2011, Ben Hutchings wrote:
> Also possibly:
> 6. DM&P/SiS Vortex86 and Vortex86SX. These supposedly have all
> 586-class features except an FPU, and we could probably keep FPU
> emulation for them.

FWIW, I do run Debian on such systems albeit with a custom kernel.
Given those CPU tend to be used in an "embedded" context I guess
it's ok if the official kernel does not support them. But it would be
nice if Debian's userspace could be kept compatible. Not sure what this
requires though...

Cheers,
--
Raphaël Hertzog ◈ Debian Developer

Pre-order a copy of the Debian Administrator's Handbook and help
liberate it: http://debian-handbook.info/go/ulule-rh/


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