Subject: Re: scheduler woes on MPACPI kernel
To: Daniel Carosone <>
From: Teemu Rinta-aho <>
List: current-users
Date: 01/19/2005 10:10:19
Daniel Carosone wrote:
> On Tue, Jan 18, 2005 at 11:13:25PM +0100, Johnny Billquist wrote:
>>But why shouldn't a hyperthreaded cpu be able to that much in parallel. 
>>It's been a few years since I last studied computer architectures, so I'm 
>>probably a bit rusty. But isn't a hyperthreaded cpu actually two cpu 
>>cores, but they share the bus interface, caches, and everything else 
>>outside the actual cpu core (by which I mean alu and registers). 
> No, it's actually almost exactly the inverse.  It's one cpu core (ie,
> pool of arithmetic units and so forth), with parts of the outer
> presentation duplicated to look like two cpus.  The two virtual cpus
> share the resources of the core, the idea being that by clever
> scheduling they can eke out some spare cycles from units that would
> otherwise have been idle or stalled working on a single instruction
> stream.

I guess the trend is, though, that in the future there will
be several CPU cores inside one "CPU box".. If you can't
increase rpm, increase cylinders (= cubic inches), right? :-)


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