2.4.x & Celeron = very slow system

2.4.x & Celeron = very slow system

[Serguei I. Ivantsov]

Hello!

I have a BIG problem with 2.4.x kernels.

With 2.4.x kernel my system (Celeron (Coppermine) 850Mhz (100x8.5)
256Mb i810) behaves like slow i386sx.

For example, when I extract 25MB gzip file on 2.2.19 kernel - it
takes about 12 seconds, but with 2.4.8(9) - 6(!) MINUTES on the SAME
system...

The only idea is that 2.4.x kernel turns off cache (L1 & L2) on
processor (on my cpu). How can I check it? Any ideas?


-- 
Best regards,
 Serguei                          mailto:administrator@svitonline.com

Re: 2.4.x & Celeron = very slow system

[Dave Jones]

On Sun, 19 Aug 2001, Serguei I. Ivantsov wrote:

> With 2.4.x kernel my system (Celeron (Coppermine) 850Mhz (100x8.5)
> 256Mb i810) behaves like slow i386sx.
>
> For example, when I extract 25MB gzip file on 2.2.19 kernel - it
> takes about 12 seconds, but with 2.4.8(9) - 6(!) MINUTES on the SAME
> system...
>
> The only idea is that 2.4.x kernel turns off cache (L1 & L2) on
> processor (on my cpu). How can I check it? Any ideas?

No, we don't do any such frobbing of the cache control registers.
It is enabled in the BIOS right ?

Another thing that it might be, is if you're using ACPI instead of
APM, the cpu-idle may be causing the CPU to run slower than usual
though throttling.

Although, I've not seen this happen to the extent of what you're
reporting.  If you are running with an ACPI kernel, try booting
with an APM kernel instead to see if it makes a difference.

regards,

Dave.

-- 
| Dave Jones.        http://www.suse.de/~davej
| SuSE Labs

Re[2]: 2.4.x & Celeron = very slow system

[Serguei I. Ivantsov]

Hello Dave,

Sunday, August 19, 2001, 4:22:40 PM, you wrote:

DJ> On Sun, 19 Aug 2001, Serguei I. Ivantsov wrote:

>> With 2.4.x kernel my system (Celeron (Coppermine) 850Mhz (100x8.5)
>> 256Mb i810) behaves like slow i386sx.
>>
>> For example, when I extract 25MB gzip file on 2.2.19 kernel - it
>> takes about 12 seconds, but with 2.4.8(9) - 6(!) MINUTES on the SAME
>> system...
>>
>> The only idea is that 2.4.x kernel turns off cache (L1 & L2) on
>> processor (on my cpu). How can I check it? Any ideas?

DJ> No, we don't do any such frobbing of the cache control registers.
DJ> It is enabled in the BIOS right ?
It is enabled in BIOS.
DJ> Another thing that it might be, is if you're using ACPI instead of
DJ> APM, the cpu-idle may be causing the CPU to run slower than usual
DJ> though throttling.
I'd disabled APM support at all when configuring kernel.
DJ> Although, I've not seen this happen to the extent of what you're
DJ> reporting.  If you are running with an ACPI kernel, try booting
DJ> with an APM kernel instead to see if it makes a difference.
Maybe there is some software to test which subsystem fails
(cpu,vm,etc)? Is it possible that software from RH7.0 distribution
can't work correctly with new kernel?

-- 
Best regards,
 Serguei                            mailto:administrator@svitonline.com

Re: Re[2]: 2.4.x & Celeron = very slow system

[Dave Jones]

On Sun, 19 Aug 2001, Serguei I. Ivantsov wrote:

> DJ> Another thing that it might be, is if you're using ACPI instead of
> DJ> APM, the cpu-idle may be causing the CPU to run slower than usual
> DJ> though throttling.
> I'd disabled APM support at all when configuring kernel.

And ACPI too ?

regards,

Dave.

-- 
| Dave Jones.        http://www.suse.de/~davej
| SuSE Labs

Re: 2.4.x & Celeron = very slow system

[Alan Cox]

> With 2.4.x kernel my system (Celeron (Coppermine) 850Mhz (100x8.5)
> 256Mb i810) behaves like slow i386sx.
> For example, when I extract 25MB gzip file on 2.2.19 kernel - it
> takes about 12 seconds, but with 2.4.8(9) - 6(!) MINUTES on the SAME
> system...
> The only idea is that 2.4.x kernel turns off cache (L1 & L2) on
> processor (on my cpu). How can I check it? Any ideas?

We don't touch the caches like that. First guess is to disable the ACPI
support, because we've seen that do a million bogus things