[Xen-users] Warning about TLS emulation mode won't go away, Xen 3.0.3 on Ubuntu 6.10 Edgy

[Tobias Galitzien <tg@xxxxxxx>]

Hello Xen users!

I have compiled Xen 3.0.3 from source on Ubuntu 6.10 "Edgy" on a Dell
PowerEdge 1950 with two Intel Xeon CPUs.

By distrubution default, the package libc6-i686 is installed which 
contains the files in /lib/tls. Thus, for Xen I deinstalled this package 
so I have no directory /lib/tls at all.
Strange I get this very well-known warning anyway, even with no /lib/tls 
in place:
***************************************************************
***************************************************************
** WARNING: Currently emulating unsupported memory accesses  **
**          in /lib/tls glibc libraries. The emulation is    **
**          slow. To ensure full performance you should      **
**          install a 'xen-friendly' (nosegneg) version of   **
**          the library, or disable tls support by executing **
**          the following as root:                           **
**          mv /lib/tls /lib/tls.disabled                    **
** Offending process: init (pid=1)                           **
***************************************************************
***************************************************************

So what else might I have to delete/move/change?

ldd /sbin/init says:

        linux-gate.so.1 =>  (0xbfffe000)
        libc.so.6 => /lib/libc.so.6 (0xb7e53000)
        /lib/ld-linux.so.2 (0xb7f79000)

I then found a package named libc6-xen which contains a "xen optimized 
version on libc6". It installs a bunch of files in 
/lib/tls/i686/cmov/nosegneg and a xen.conf in /etc/ld.so.conf.d with one 
line saying "hwcap 0 nosegneg".
Now ldd /sbin/init says something different:

        linux-gate.so.1 =>  (0xbfffe000)
        libc.so.6 => /lib/tls/i686/cmov/nosegneg/libc.so.6 (0xb7ddc000)
        /lib/ld-linux.so.2 (0xb7f19000)

which seemed to me a goot thing because now init should no longer be 
offending. But the Xen warning persists after reboot.
Is maybe the warning the problem? Can/should I ignore it? A quick test 
with unixbench tells me there is indeed a performance waste of about a 
quarter compared to a normal kernel with tls enabled in libc6.
What else can I try? It seems to me there is something special with 
Ubuntu. Some months ago I tried the same thing with Debian Sarge and 
after moving away /lib/tls the warning disappeared. Unfortunately I 
cannot do it here because part of the hardware is not supported by the 
Sarge installer.

Thanks a lot in advance for any hint!


Tobias


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