Re: Distinguish real vs. virtual CPUs?

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Tom Vier wrote:
On Tue, Mar 22, 2005 at 04:26:47PM -0500, Bill Davidsen wrote:

It's not clear if that's bizarre practice on AMD system boards or if it's mis-reported. Of course Tom may be running a NUMA setup, in which case I won't guess what's expected to be displayed. I've added him to the CC list, in hopes of comment.


It's numa (two cores, one ram ctrlr per core, one core per package). I'm
running an x86 kernel, btw, not 64bit. I have CONFIG_X86_HT set, and it
looks like it gets the pkg id from the apic (there's only one in multicore
packages?), but i might be reading it wrong.

My dmseg overflows before syslog starts, so all i could gather is:

Thanks, Tom. I suspect that NUMA has issues of its own in this area. I always set up the kernel buffer size and run dmesg with -s200000 or so on machines which tend to be overly verbose.

I leave it to someone really expert to figure out how to tell the actual number of sockets, cores, and siblings. I think the system scheduler may want this info, but I certainly don't intend to start 2nd guessing the kernel on this stuff. The current scheduler does a pretty good job of handling HT now, I'm not about to try and do better.

Interesting thought, I believe the IBM chip for PS not only has many cores, but one article said they were not all the same. That, and thoughts of someone running an SMP system with chips having non-identical sibling count make me glad someone else is doing the scheduler.

Mar 23 12:04:25 zero kernel: Brought up 2 CPUs
Mar 23 12:04:25 zero kernel: CPU0 attaching sched-domain:
Mar 23 12:04:25 zero kernel:  domain 0: span 3
Mar 23 12:04:25 zero kernel:   groups: 1 2
Mar 23 12:04:25 zero kernel: CPU1 attaching sched-domain:
Mar 23 12:04:25 zero kernel:  domain 0: span 3
Mar 23 12:04:25 zero kernel:   groups: 2 1

I don't know how the scheduling domains work, and i'm too busy to look it up
right now.



--
   -bill davidsen ([email protected])
"The secret to procrastination is to put things off until the
 last possible moment - but no longer"  -me
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