RE: perf events ring buffer memory barrier on powerpc

From: Victor Kaplansky
Date: Fri Nov 01 2013 - 12:32:29 EST

"David Laight" <David.Laight@xxxxxxxxxx> 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

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