Re: [PATCH 00/16] Remove the direct map

[Hongyan Xia <hx242@xxxxxxx>]

On Tue, 2020-06-02 at 09:08 +0000, Wei Liu wrote:
> On Fri, May 01, 2020 at 02:53:08PM +0100, Hongyan Xia wrote:

[...]

> Not sure about hiding EPT. I will leave this question to Jan and
> Andrew...

Quick update on performance numbers. I have seen noticeable performance
drop if we need to map and unmap EPT. This translates to up to 10%
degredation in networking and database applications.

With EPT always mapped (not considering it as secrets), I have not seen
any noticeable performance drop in any real-world applications. The
only performance drop is from a micro-benchmark that programs HPET in a
tight loop (abusing MMIO page table walks), and the worst case is
around 10% to 15%.

Note that all above results are based on the mapcache rewrite patch

4058e92ce21627731c49b588a95809dc0affd83a.1581015491.git.hongyxia@xxxxxxxxxx
to fix the mapcache lock contention first.

Hongyan