Re: X15 alpha release: as fast as TUX but in user space (fwd)

From: H. Peter Anvin (
Date: Sun Apr 29 2001 - 00:13:11 EST

Followup to: <>
By author: Richard Gooch <>
In newsgroup:
> >
> > In x86-64 there are special vsyscalls btw to solve this problem that export
> > a lockless kernel gettimeofday()
> Whatever happened to that hack that was discussed a year or two ago?
> The one where (also on IA32) a magic page was set up by the kernel
> containing code for fast system calls, and the kernel would write
> calibation information to that magic page. The code written there
> would use the TSC in conjunction with that calibration data.
> There was much discussion about this idea, even Linus was keen on
> it. But IIRC, nothing ever happened.

We discussed this at the Summit, not a year or two ago. x86-64 has
it, and it wouldn't be too bad to do in i386... just noone did.


<> at work, <> in private!
"Unix gives you enough rope to shoot yourself in the foot."
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