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From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
Date: Tue, 26 Feb 2008 01:47:21 -0800
To: Jeff Roberson <jroberson@chesapeake.net>
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Cc: David Xu <davidxu@freebsd.org>, current@freebsd.org
Subject: Re: Topology aware scheduling algorithm.
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On Feb 25, 2008, at 11:51 PM, Jeff Roberson wrote:

>
> On Tue, 26 Feb 2008, David Xu wrote:
>
>> Jeff Roberson wrote:
>>
>>> I think our identcpu.c already detects this information.  That's  
>>> what I'm using.  Although I assume that all cpus are identical  
>>> and fall back on a flat topology if this isn't the case.  I'd  
>>> like to start including more cache information though.
>>> Jeff
>>
>> The patch does not assume all cpus are identical, in theory, one  
>> can have a machine with one cpu is 4-core and another is 2-core cpu.
>> only one place needs to be fixed in the patch,the global variable
>> cpu_feature, which is easy to fix for the patch.
>
>                         cpuid_count(4, cache_level, regs);
> 			if ((regs[0] & 0x1f) == 0)
> 				break;
> 			threads_per_cache = ((regs[0] & 0x3ffc000) >> 14) + 1;
>
> Does this work on all intel/amd cpus?

That won't work on AMD, as they don't support cpuid 4, as far as I know.

-- Suleiman