[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PULL 17/19] target-i386: Support "invariant tsc" flag
From: |
Marcelo Tosatti |
Subject: |
Re: [Qemu-devel] [PULL 17/19] target-i386: Support "invariant tsc" flag |
Date: |
Fri, 8 Aug 2014 18:42:26 -0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Chen Liang,
On Fri, Aug 08, 2014 at 07:07:59AM +0000, chenliang (T) wrote:
> Hi,
> We found that value of host cpus tsc are same to echo other when host has
> invariant tsc flag.
What you mean exactly?
Do you have a test program?
> But it is not in vm. The problem is that offset of vcpus tsc are not equal.
> The offset is set when
> vcpu is created. Is it ok to set same offset? And is it reasonable?
>
> Best regards
> Chen Liang
The code at kvm_write_tsc(), in the kernel (arch/x86/kvm/x86.c), should
adjust the vcpu tsc offsets properly resulting in cross SMP TSCs being
equal in the VM.