[concurrency-interest] JSR-133 Cookbook and exit monitor
boehm at acm.org
Wed Oct 8 14:12:54 EDT 2014
The original transformation, moving a trailing "y = 43" into a critical
section, can typically happen on a weakly ordered architecture like ARM as
a result of hardware reordering. On such an architecture, an ordinary
lock release is essentially a fence followed by an unordered CAS (or on
ARMv8, a CAS with release semantics). There is nothing to prevent a later
store to y from becoming visible before the CAS releasing the lock. No
compiler transformations required ...
On Wed, Oct 8, 2014 at 7:34 AM, Vitaly Davidovich <vitalyd at gmail.com> wrote:
> Yes, as Doug pointed out, the "roach motel" semantics is just an allowed
> reordering -- compiler will hopefully not stuff more things into a critical
> section unless it has strong evidence that it's worthwhile. I'd actually
> be curious to hear from anyone that's seen such a transformation.
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