[concurrency-interest] RFR: 8065804: JEP 171: Clarifications/corrections for fence intrinsics

Martin Buchholz martinrb at google.com
Tue Dec 16 19:06:58 EST 2014


On Thu, Dec 11, 2014 at 1:08 AM, Andrew Haley <aph at redhat.com> wrote:
> On 11/12/14 00:53, David Holmes wrote:
>> There are many good uses of storestore in the various lock-free
>> algorithms inside hotspot.
>
> There may be many uses, but I am extremely suspicious of how good
> they are.  I wonder if we went through all the uses of storestore in
> hotspot how many bugs we'd find.  As far as I can see (in the absence
> of other barriers) the only things you can write before a storestore
> are constants.

Hans has provided us with the canonical writeup opposing store-store
and load-load barriers, here:
http://www.hboehm.info/c++mm/no_write_fences.html
Few programmers will be able to deal confidently with causality
defying time paradoxes, especially loads from "the future".


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