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List:       netbsd-tech-kern
Subject:    Re: playing with qemu's SMP support (i386)
From:       Thor Lancelot Simon <tls () rek ! tjls ! com>
Date:       2005-12-23 13:21:14
Message-ID: 20051223132114.GA12255 () panix ! com
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On Fri, Dec 23, 2005 at 04:04:09AM +0000, Rui Paulo wrote:
> On 2005.12.23 04:10:55 +0100, Hubert Feyrer wrote:
> | 
> |  * qemu claims to support upto 255 CPUs, but when started with 128,
> |    NetBSD only recognizes the first 20:
> 
> I already told you this on ICB, but here it goes again so that other
> can know:
> 
> In arch/i386/include/cpu.h
> 
> #if defined(MULTIPROCESSOR)
> 
> #define X86_MAXPROCS            32      /* because we use a bitmask */

20 is less than 32.

This reminds me again that we had patches from cl for processor affinity
in the scheduler (which would give us a nice performance boost on the
larger amd64 machines that are starting to show up, now that Newisys
has a chipset with a hypertransport switch in the middle) which we
never did anything with because they used a bitmask, so they supported
only 32 run queues.  Sigh.

Thor
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