KVMでEPTだと従来よりもTLB missのコストが上がってるからページテーブルサイズを
大きくするメリットが大きくて、だから透過的hugepageが必要で、実際に性能向上が
あって・・・とか説明してる。

で、6%なんてたいした改善じゃないというLinusに「ちがうちがう。hostは+50%以上改善していて
その影響でゲストが何も変更しないでも6%改善するって言ってるんだよ」とAndreaが
説明している


On Tue, 6 Apr 2010, Andrea Arcangeli wrote:
>
> In short I first measured the page fault improvement in host (~+50%
> faster, sure that has nothing to do with pmd_huge or the tlb miss, I
> said I mentioned it just for curiosity in fact), then measured the tlb
> miss improvement in host (a few percent faster as usual with
> hugetlbfs) then measured the boost in guest if host uses hugepages
> (with no guest kernel change at all, just the tlb miss going faster in
> guest and that boosts the guest kernel compile 6%) and then some other
> test with dd with all combinations of host/guest using hugepages or
> not, and also with dd run on bare metal with or without hugepages.

Yeah, sorry. I misread your email - I noticed that 6% improvement for
something that looked like a workload I might actually _care_ about, and
didn't track the context enough to notice that it was just for the "host
is using hugepages" case.

So I thought it was a more interesting load than it was. The
virtualization "TLB miss is expensive" load I can't find it in myself to
care about. "Get a better CPU" is my answer to that one,

Linus


意訳:いやーすまんすまん。君のメールを誤読してたよ。うん、これは興味深いね、
僕は「The virtualization "TLB miss is expensive" load」について気づいてなかった
じゃあ、これが僕の新しい返事だよ


もっとマシなCPU買え