* Andi Kleen <[EMAIL PROTECTED]> wrote:
> On Wed, Jan 09, 2008 at 04:22:08PM +0100, Ingo Molnar wrote:
> >
> > * Andi Kleen <[EMAIL PROTECTED]> wrote:
> >
> > > > nope, it's a 64-bit setup/dependency bug/problem: the vsyscall mappings
> > > > are installed via an __initcall, and that's too late for early use. The
> > > > combo patch below fixed the crash for me, does it work on your box too?
> > >
> > > That gives
> > >
> > > /home/lsrc/quilt/linux/arch/x86/kernel/setup_64.c: In function
> > > 'setup_arch':
> > > /home/lsrc/quilt/linux/arch/x86/kernel/setup_64.c:468: error: implicit
> > > declarati
> > > on of function 'map_vsyscall'
> >
> > i guess you have an old repository.
>
> I just applied the patch you sent out against yesterday's git-x86.
then you have a truly ancient x86.git repository ;-)
think of x86.git#mm as an open development tree. It's high-flux, based
against Linux-bleeding-edge, it's frequently updated (daily, sometimes
hourly), breakages are possible (and likely) and fixes and other
feedback is more than welcome. And please feel free to complain about
patches that are included. (like you did in the past) Also please try to
post your patches as early as possible instead of in big chunks - last
week's 75 patches patchbomb from you was (and still is) ... challenging
;-)
> > since yesterday there's a full barrier around rdtsc.
>
> Great.
i have measured the impact of the barriers and it was in the noise
level. Barriers are notoriously easy to get wrong (because almost
nothing tells the programmer that they are wrong), that's why i did this
barrier-safe rdtsc() [& friends]. We had so much trouble with RDTSC
during the past 10 years of its existence that being a bit more
conservative with it is the only really maintainable option.
Ingo
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