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barry
Apprentice
Joined: 01 May 2002
Posts: 170
Location: UK
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 Posted: Sun May 25, 2003 1:21 pm Post subject: Should APIC be enabled? |
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| Is there any point in enabling APIC in the kernel for single-CPU systems? I've tried it, and have noticed that the ERR value in /proc/interrupts gradually increases when it's enabled, while it remains at 0 otherwise. |
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shawk
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Joined: 12 Nov 2002
Posts: 42
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| Posted: Sun May 25, 2003 4:42 pm Post subject: |
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APIC in itself is a good thing(tm). It basically provides additional IRQs which helps a lot when you have many different expansion cards installed. No more sound, network and graphics card sharing int11.
But then again, APIC is farily new onto the market (about 1 year) and not all implementaions are working properly. In addtion to that, APIC on Via boards is currently b0rked on the 2.5 kernels and not useful on the 2.4 kernels. APIC on Intel boards usually works quite well.
So, if you have a stable system no need to fiddle with APIC. There is no performance increase or other benefit to it, yet.
--
Shawk |
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barry
Apprentice
Joined: 01 May 2002
Posts: 170
Location: UK
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| Posted: Sun May 25, 2003 10:41 pm Post subject: |
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On this Asus A7N8X (NForce2), everything seems to run ok with APIC enabled, but the ERR number slowly increases. After 2h45 min uptime it's currently sitting at 974.
In Windows XP I get the extra IRQs (about 24?) while in Linux it's just the normal set. |
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sth
n00b
Joined: 20 Apr 2003
Posts: 4
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| Posted: Mon May 26, 2003 6:20 pm Post subject: |
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| Enabling the APIC on the a7n8x causes problems on Windows. Maybe under Linux too? People having problems with sound distortions etc. should disable it. |
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sputnik1969
Guru
Joined: 08 Aug 2002
Posts: 401
Location: Berlin / Germany
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| Posted: Mon May 26, 2003 9:54 pm Post subject: |
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| shawk wrote: | But then again, APIC is farily new onto the market (about 1 year) and not all implementaions are working properly. In addtion to that, APIC on Via boards is currently b0rked on the 2.5 kernels and not useful on the 2.4 kernels. APIC on Intel boards usually works quite well.
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No, that isn't really right...
1) APIC exists longer than 1 Year, even my Pentium2 350 w/ BX supports it...
2) It's definetly NOT a broken BIOS problem! Until Kernel 2.4.18 everything works fine using APIC on my SIS735 (K7S5A) but since 2.4.19 everything sucks if APIC is enabled in BIOS and Kernel has APIC-support...
If APIC support is in kernel and switched OFF in BIOS, APIC WORKS unter Linux, but not in Windows. If APIC is switched ON, it works in WIndows, but nut with Linux...
My Conclusion: APIC (Initialization) Support is broken in Kernels > 2.4..18
So i'm using APIC (ON in BIOS) unter W2K and removed it from my Linux-Kernel...
P.S: This seems to be just an AMD problem, Intel Systems seem to be more stable with it...
_________________
'Cynic' is a word invented by optimists to criticize realists. - Nigel. In the ocean of Night by Gregory Benford
"Zyniker" ist ein Wort das Optimisten erfunden haben um Realisten zu kritisieren. - Nigel. Im Meer der Nacht von Gregory Benford |
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