Re: [PATCH v4 0/6] Micro-optimize vclock_gettime

From: Ingo Molnar
Date: Tue May 17 2011 - 15:27:22 EST

* Andy Lutomirski <luto@xxxxxxx> wrote:

> It's even easier than that: there are no syscall numbers involved. There are
> four separate entry points, one for each vsyscall.
> (It turns out that one of them has been broken and just segfaults since 2008
> (a4928cff), so we only have to emulate three of them.)
> On KVM on Sandy Bridge, I can emulate a vsyscall that does nothing in 400ns
> or so. I'll try to make this code emulate real vsyscalls over the weekend.

Very nice!

> This was much easier than I expected.

Hey, looking back at a working patch always makes it seem easy ;-)


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