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Date: Tue, 17 May 2011 21:27:01 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Andy Lutomirski <luto@MIT.EDU>
Cc: Thomas Gleixner <tglx@linutronix.de>, Andi Kleen <andi@firstfloor.org>,
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Subject: Re: [PATCH v4 0/6] Micro-optimize vclock_gettime
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* Andy Lutomirski <luto@MIT.EDU> 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 ;-)

Thanks,

	Ingo