Messages in this thread | | | Date | Sun, 2 Feb 2003 02:28:20 +0100 | From | Willy Tarreau <> | Subject | [Nearly Solved]: APIC routing broken on ASUS P2B-DS |
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On Tue, Jan 28, 2003 at 07:06:29AM +0100, Willy Tarreau wrote: > On Mon, Jan 27, 2003 at 04:49:06PM -0800, Simon Kirby wrote: > > Something broke between 2.4.20 and 2.4.21-pre3 which is causing > > interrupts to not be routed the second CPU. I saw the problem on one box > > and copied the kernel to another which then had the same problem (both > > ASUS P2B-DS boards, one with PIII CPUs, one with PII CPUs).
Hi !
I noticed that 2.4.21-pre4 had the same problem whereas -ac1 and -aa1 worked fine. But unfortunately, this was unrelated since both use irq_balance which seems to work around or fix the problem. So I searched back the earlier versions, and finally narrowed this problem down to the introduction of CONFIG_X86_NUMA and associated code in 2.4.21pre1.
If I compile my kernel for an SMP K7, only CPU0 gets the interrupts. But if I enable CONFIG_X86_CLUSTERED_APIC by enabling either CONFIG_X86_NUMAQ or CONFIG_X86_SUMMIT (CONFIG_X86_NUMA alone isn't enough), then I get my interrupts distributed across both CPUs. This is on an Asus A7M266D with 2 Athlon XP 1800+. I don't know if this option can affect performance or stability. BTW, the system runs in Flat APIC mode, as reported at boot time. I can provide dmesg on request, but didn't want to pollute the list.
I looked through the code but since I don't know much about APIC, I didn't understand the changes nor how they would affect what I observed.
Anyone has any clue ?
Cheers, Willy
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