From: Paolo Bonzini <pbonzini@redhat.com>
To: Wei Huang <wei@redhat.com>, afaerber@suse.de
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/1] target-i386: prevent users from setting threads>1 for AMD CPUs
Date: Tue, 07 Oct 2014 23:36:08 +0200 [thread overview]
Message-ID: <54345CC8.8050806@redhat.com> (raw)
In-Reply-To: <54345843.8070703@redhat.com>
Il 07/10/2014 23:16, Wei Huang ha scritto:
> It isn't a bug IMO. I tested various combinations; and current QEMU
> handles it very well. It converts threads=n to proper
> CPUID_0000_0001_EBX[LogicalProcCount] and CPUID_8000_0008_ECX[NC]
> accordingly for AMD.
So if it ain't broken, don't fix it. :)
>> I am worried that the default CPU is an AMD one when KVM is disabled,
>> and thus "qemu-system-x86_64 -smp threads=2" will likely be broken.
>
> "-smp threads=2" will be rejected by the patch.
Yeah, I am afraid that is an incompatible change, and one more reason
not to do this. AMD not selling hyperthreaded processors does not mean
that they could not be represented properly with the CPUID leaves that
AMD processors support.
Paolo
> Unless the meaning of
> threads is not limited to threads-per-core, shouldn't end users use
> "-smp 2" in this case or something like "-smp 2,cores=2,sockets=1"?
next prev parent reply other threads:[~2014-10-07 21:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 19:44 [Qemu-devel] [PATCH 1/1] target-i386: prevent users from setting threads>1 for AMD CPUs Wei Huang
2014-10-07 20:58 ` Paolo Bonzini
2014-10-07 21:16 ` Wei Huang
2014-10-07 21:36 ` Paolo Bonzini [this message]
2014-10-08 0:41 ` Wei Huang
2014-10-08 7:47 ` Paolo Bonzini
2014-10-09 20:22 ` Wei Huang
2014-10-09 21:08 ` Paolo Bonzini
2014-10-09 22:16 ` Eduardo Habkost
2014-10-21 15:11 ` Wei Huang
-- strict thread matches above, loose matches on Subject: below --
2014-10-07 19:17 Wei Huang
2014-10-07 19:42 ` Wei Huang
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