Re: cannot set up LDT for thread-local storage

[John Hayward <John.C.Hayward%wheaton.edu@localhost>]

> > > I found pr 33487.
> > > This was for dom0 i386 for NetBSD 3.99.19.
> > >
> > > I have been running a version of firefox-linux on a dom0 i386
> > > NetBSD-4.0 without problem.  Maybe I was just lucky.
> > Here is additional info
> > Xen 3.0 i386  dom0 NetBSD-4.0  i386 dom0 firefox-linux-2 works
> > Xen 3.3 amd64 dom0 NetBSD-4.99 i386 domu firefox-linux-2 works
> > Xen 3.3 amd64 dom0 NetBSD-4.99 i386 domu firefox-linux-3 causes panic
> >        (with LDT option on)
>
> This is an artifact of which Linux pthread library the application's
> linked to.  The old library used a method of allocation for thread local
> storage which Xen couldn't efficiently accomodate, so under Xen it was
> slow as molasses.  The new one uses a method which requires adjusting
> the processor's LDT (note that, oddly enough, NetBSD's libpthread
> requires neither).  Unfortunately, the USER_LDT option doesn't work
> right under NetBSD/xen.
Am I correct in assuming that if USER_LDT were fixed in NetBSD then
Xen could implement efficently Linux pthread newer library?

firefox-linux-2 is probably linked to the old pthread library (and does
not operate efficnetly under Xen) while firefox-linux-3 is probably linked
to the new pthread library.

> One suspects there might be a hungry grad student out there whou coudl
> be slipped a few hundred bucks to fix this -- but (I not being at
> present a hungry grad student) that's just a hunch.
>
> You could run a native NetBSD firefox3 binary -- they seem to work OK,
> FWIW.
I am doing that - unfortunatly there are a lot of pdfs out there and I can
get the firefox-linux to operate with those (same for java).

> Thor

Thanks for the info.
johnh...