whitehole_spin: always 0?

[Patrick Palka]

It seems that the value of the whitehole_spin counter (as viewable by +RTS
-s) is always zero, which oddly suggests that there is never any contention
on the particular atomic operation whitehole_spin is tracking (located in
copyPart in Evac.c). This may be a symptom of a bug, or it may be the case
that the atomic operation is not necessary. (Or perhaps contention is just
very rare. But if contention is rare, why is this operation being counted
in particular?) Either way, I think this is a bit strange and probably
worth investigating.

Patrick
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/ghc-devs/attachments/20130725/bae51896/attachment.htm>