Re: [PATCH v2 07/16] KVM: MMU: introduce for_each_pte_list_spte
From: Takuya Yoshikawa
Date: Fri Apr 20 2012 - 21:01:15 EST
Sorry for the delay.
On Wed, 18 Apr 2012 12:01:03 +0800
Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> wrote:
> > I have checked dirty-log-perf myself with this patch [01-07].
> >
> > GET_DIRTY_LOG for 1GB dirty pages has become more than 15% slower.
> Thanks for your test!
>
> Unbelievable, i will do more test and check it more carefully.
GET_DIRTY_LOG now traverses rmap lists intensively.
So only a small change can affect the performance when there are many
dirty pages.
> Could you please open your tool, then i can reproduction it and find the
> real reason?
It's already in kvm unit tests!
> I will check whether your tool is better then kernbench/autotest after
> review your tool.
Let's focus on "lock-less" now: so dirty-log-perf is not needed now.
I think you failed to appeal the real advantage of your "lock-less" approach!
I will write about this on v3-threads.
Thanks,
Takuya
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