Re: [patch 2/2] x86 amd fix cmpxchg read acquire barrier

From: Mathieu Desnoyers
Date: Sat May 02 2009 - 11:55:29 EST


* Pavel Machek (pavel@xxxxxx) wrote:
> On Wed 2009-04-22 16:18:54, Mathieu Desnoyers wrote:
> > http://google-perftools.googlecode.com/svn-history/r48/trunk/src/base/atomicops-internals-x86.cc
> >
> > says
> >
> > " // Opteron Rev E has a bug in which on very rare occasions a locked
> > // instruction doesn't act as a read-acquire barrier if followed by a
> > // non-locked read-modify-write instruction. Rev F has this bug in
> > // pre-release versions, but not in versions released to customers,
> > // so we test only for Rev E, which is family 15, model 32..63 inclusive.
>
> Could we be more careful here and catch the F pre-release versions,
> too? Stepping should help there...
>

Yes, I guess for F pre-releases we're stucked unless AMD provides more
information. Dtrace did not seem to bother about F pre-release versions
though, neither did Google.

Mathieu

> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Mathieu Desnoyers
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