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From: James Stevens <James.Stevens@communitydns.net>
To: kvm@vger.kernel.org
Subject: Re: stability issue with KVM using SMP
Date: Tue, 16 Sep 2008 12:46:22 +0100	[thread overview]
Message-ID: <48CF9C8E.5040800@communitydns.net> (raw)
In-Reply-To: <48CF6D79.6090607@communitydns.net>

Further to my previous report..

I have just noticed that, where the host is running on the dual 
"Quad-Core AMD Opteron(tm) Processor 2352" (family 16, model 2) the 
kernels in the *guest* machines (usually 2.6.26) are reporting "WARNING: 
This combination of AMDprocessors is not suitable for SMP." - presumably 
this is why my SMP isn't stable!

The kernel in that host machine (2.6.26.2) does *not* report the messages.



However, where the host is a single "AMD Athlon(tm) 64 X2 Dual Core 
Processor 4000+" (family 15, model 107) the guest kernels do not report 
the WARNING above - but I've not actually run any SMP guest on that 
host, so don't know if it would work or not.



The warning seems to be due to a processor capability test in 
"arch/x86/kernel/smpboot.c" - "add_taint(TAINT_UNSAFE_SMP);"

Its not clear to me why one guess is failing this test and the other 
passing, because both guests are seeing "QEMU Virtual CPU version 
0.9.1", family 6, model 2 (according to "/proc/cpuinfo").

Although most kernels on the Athlon host are running 2.6.21 not 2.6.26




James

      reply	other threads:[~2008-09-16 11:47 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-16  8:25 stability issue with KVM using SMP James Stevens
2008-09-16 11:46 ` James Stevens [this message]

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