Re: Memory ordering issue in LWLockRelease, WakeupWaiters, WALInsertSlotRelease

From: Ants Aasma <ants(at)cybertec(dot)at>
To: knizhnik <knizhnik(at)garret(dot)ru>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Memory ordering issue in LWLockRelease, WakeupWaiters, WALInsertSlotRelease
Date: 2014-02-12 14:10:51
Message-ID: CA+CSw_s90knpKEmbYpFAV-zP5-=DPKzi3r-_oLReHreE8w62kw@mail.gmail.com
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On Wed, Feb 12, 2014 at 4:04 PM, knizhnik <knizhnik(at)garret(dot)ru> wrote:
> Even if reordering was not done by compiler, it still can happen while
> execution.
> There is no warranty that two subsequent assignments will be observed by all
> CPU cores in the same order.

The x86 memory model (total store order) provides that guarantee in
this specific case.

Regards,
Ants Aasma
--
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de

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