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Re: [Xen-users] Xen and TLS, -mno-tls-direct-seg-refs needed?

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Xen and TLS, -mno-tls-direct-seg-refs needed?
From: Javier Guerra <javier@xxxxxxxxxxx>
Date: Fri, 11 Aug 2006 05:45:03 -0500
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On Thursday 10 August 2006 5:26 pm, Sven Köhler wrote:
> On 32-bit platforms?
>
> Does it mean, that i don't need to use that "-mno-tls-direct-seg-refs"
> on 64-Bit platforms?

right.  the problem is that on 32bit x86 NPTL uses a weird trick to store TLS 
on negative segment references.  in other platforms that trick isn't used, 
and there's no problem with Xen.

the "-mno-tls-direct-seg-refs" flag turns off the trick for 32bit x86, so it's 
forced to use a saner approach.  in theory it's slower than the default way, 
but much faster than being emulated by Xen

-- 
Javier

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