That is what I would prefer. I was trying to not disturb things too much :). Please bring the changes over!
-Nathan On Wed, Jul 30, 2014 at 03:18:44PM -0400, George Bosilca wrote: > Why do you want to add new versions? This will lead to having two, almost > identical, sets of atomics that are conceptually equivalent but different > in terms of code. And we will have to maintained both! > I did a similar change in a fork of OPAL in another project but instead of > adding another flavor of atomics, I completely replaced the available ones > with a set returning the old value. I can bring the code over. > George. > > On Tue, Jul 29, 2014 at 5:29 PM, Paul Hargrove <phhargr...@lbl.gov> wrote: > > On Tue, Jul 29, 2014 at 2:10 PM, Nathan Hjelm <hje...@lanl.gov> wrote: > > Is there a reason why the > current implementations of opal atomics (add, cmpset) do not return > the > old value? > > Because some CPUs don't implement such an atomic instruction? > > On any CPU one *can* certainly synthesize the desired operation with an > added read before the compare-and-swap to return a value that was > present at some time before a failed cmpset. That is almost certainly > sufficient for your purposes. However, the added load makes it > (marginally) more expensive on some CPUs that only have the native > equivalent of gcc's __sync_bool_compare_and_swap(). > > -Paul > -- > Paul H. Hargrove phhargr...@lbl.gov > Future Technologies Group > Computer and Data Sciences Department Tel: +1-510-495-2352 > Lawrence Berkeley National Laboratory Fax: +1-510-486-6900 > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2014/07/15328.php > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2014/07/15369.php
pgpUHSVoeg0RH.pgp
Description: PGP signature
