Re: HyperThreading not working in 2.4.21-rc6-ac2

From: Rik van Riel (
Date: Fri Jun 13 2003 - 11:35:47 EST

On Fri, 13 Jun 2003, Mark Watts wrote:

> The following is a dmesg from a Dell PowerEdge 2650 server with 2 2.4Ghx
> HT capable processors. To the best of my knowledge, I have HT enabled in
> the bios but I still only see the physical processors (no siblings) even
> though the cpus are numbered as if I have siblings.
> Any suggestions?

> Kernel command line: auto BOOT_IMAGE=2421rc6ac2 ro root=801 devfs=mount
> hda=ide-scsi acpi=off

The -ac kernel drops acpitable.c, which used to detect things
like irq routing and HT "evil twin" CPUs and instead upgrades
the ACPI subsystem. I suspect you need a different ACPI setting,
though I'm not sure what it would be.

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