Re: [Xen-users] /lib/tls.disabled does not work

[William Zhou <armageddonmagic@xxxxxxx>]

Ralf Schmitt wrote:
> Hi,
>
> a new initrd will not help. Have a look a this:
>
> ***************************************************************
> ***************************************************************
> ** 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: hotplug (pid=276)                      **
> ***************************************************************
> ***************************************************************
>
> This message comes from "hotplug" ... so I have to compile hotplug
> without tls support to get rid of this boot message.
>
> Move /lib/tls to /ib/tls.disabled and ignore these messages.
>
> -ralf-
>   
Every package built without -mno-tls-direct-seg-refs has this problem, 
including Glibc.
Gentoo chooses to rebuild the whole tree to get rid of this problem. 
Taken from Gentoo Wiki:
"Some software, in particular the glibc TLS library, performs poorly 
whilst carrying
out certain operations under Xen. This will result in a ~50% performance 
penalty
running multi-threaded applications. To fix this, you must compile your 
system with
the '-mno-tls-direct-seg-refs' flag. Rebuild every package with your new 
CFLAGS."
Gentoo also choose to use Glibc with NPTL only, without Linuxthread. 
This eliminates
the use of directory /lib/tls.


William Zhou


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