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Subject: RE: perf events ring buffer memory barrier on powerpc
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To: "David Laight" <David.Laight@aculab.com>
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From: Victor Kaplansky <VICTORK@il.ibm.com>
Date: Fri, 1 Nov 2013 18:30:56 +0200
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"David Laight" <David.Laight@aculab.com> wrote on 11/01/2013 06:25:29 PM:
> gcc will do unexpected memory accesses for bit fields that are
> adjacent to volatile data.
> In particular it may generate 64bit sized (and aligned) RMW cycles
> when accessing bit fields.
> And yes, this has caused real problems.

Thanks, I am aware about this bug/feature in gcc.
-- Victor