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From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: rdtsc() in kvm-unit-tests on x86
Date: Mon, 10 Aug 2015 15:58:08 +0200
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Cc: Jintack Lim <jintack@cs.columbia.edu>,
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To: Christoffer Dall <christofferdall@gmail.com>
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On 10/08/2015 11:42, Christoffer Dall wrote:
> 
> Thanks for the reply.
> 
> On this note, is there an easy mechanism on x86 to obtain a TSC which is
> synchronized across PCPUs and between the host and the guest?
> 
> We can use the physical arch timer counter on arm64, but I'm not sure if
> there's something similar on x86?

Yes, you just use the TSC. :)  However, you first have to check that the
TSC is consistent across CPUs.  On older machines it's not, but the
kernel can detect it.

Paolo

> This is useful to trace the flow of events over an SMP system in detail.