Re: [Qemu-devel] [PATCH v4] implementing victim TLB for QEMU system emulated TLB

[Eric Blake <eblake@redhat.com>]

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On 02/03/2014 08:18 AM, Xin Tong wrote:
> This patch adds a victim TLB to the QEMU system mode TLB.
> 
> Changes from PATCH v3.
> 1. updated measurements - performance improvement is now calculated over 3 runs.
> 2. fix code as discussed on the qemu mailing list.

Th paragraph above should be moved...

> 
> QEMU system mode page table walks are expensive. Taken by running QEMU
> qemu-system-x86_64 system mode on Intel PIN , a TLB miss and walking a
> 4-level page tables in guest Linux OS takes ~450 X86 instructions on
> average.
> 
...
> 
> Although there are measurement fluctuations, the performance
> improvement is very significant and by no means in the range of
> noises.
> 
> Signed-off-by: Xin Tong <trent.tong@gmail.com>
> 
> ---

...here, after the ---.  It is nice information for the reviewers, but
has no bearing on the commit itself once accepted into git (a year from
now, we won't care how many versions it took to get to the one version
that was committed).

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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