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

H. Peter Anvin
2001-04-29T05:13:43Z

Followup to: <200104282256.f3SMuRW15999@vindaloo.ras.ucalgary.ca>
By author: Richard Gooch <rgooch@ras.ucalgary.ca>
In newsgroup: linux.dev.kernel
> >
> > 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.

-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."