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

[H. Peter Anvin]

Followup to:  <[e-mail]>
By author:    Richard Gooch <[e-mail]>
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
-- 
<[e-mail]> at work, <[e-mail]> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt