Message-ID: <4949732A.4050207@twiddle.net>
Date: Wed, 17 Dec 2008 13:46:18 -0800
From: Richard Henderson <rth@twiddle.net>
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To: Matt Turner <mattst88@gmail.com>
CC: linux-kernel@vger.kernel.org, Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Jay Estabrook <jay.estabrook@hp.com>
Subject: Re: questions about native alpha futex implementation
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Matt Turner wrote:
> Hi,
> 
> Alpha uses a generic futex implementation, which causes some problems [1].
> 
> I've read through the code, and it appears as if the implementation
> could be done by using the ldq_l/stq_c instructions, relatively easy I
> might add. I'm definitely interested in implementing this, but first...
> 
> I have only a few questions.
> 
> 1) What are the benefits of a native futex implementation, other than
> fixing the glibc test failures?
> 2) Is there a technical reason it hasn't been implemented on Alpha?
> 3) Am in correct that it could be done with ldq_l/stq_c instructions?

I think all the futex stuff is 32-bits wide, so ldl_l/stl_c.
You can pretty much just copy the powerpc version, as that
platform also uses load-locked/store-conditional operations.


r~
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