Summarize #7602

Austin Seipp austin at
Tue Feb 4 21:31:28 UTC 2014

TL;DR OS X suffers a performance hit when build with llvm-gcc/clang.
The binary builds are built this way. The fix I outlined in the ticket
(a fast `pthread_getspecific`/`pthread_setspecific`) could still work
to recover most of the performance, but Apple accidentally messed up
the Mavericks source code release, so I'm not sure if anything
regarding the pthread implementation has changed. If it hasn't, then I
think it should be reasonably easy to fix with some testing.

(The ticket is a bit of a long and dry read I'm afraid.)

On Tue, Feb 4, 2014 at 3:22 PM, Andrew Farmer <afarmer at> wrote:
> I know that #7602 has been mentioned as a final loose end in the RC. I was
> wondering if someone in the know could summarize its status in regards to
> how it effects GHC users.
> Feel free to be blisteringly brief... ;-) I'm just looking for things like:
> "this is a non-issue on modern OS X/Clang" or "it'll be fixed soon just be
> patient" or "we've done our part, this is Apple's problem now".
> I gave the trac thread a read-through, but there seems to be several degrees
> of flexibility/workarounds, so I'm still not sure if this is something I
> should worry about on my OS X machine.
> Thanks for your cycles!
> Andrew
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> ghc-devs at


Austin Seipp, Haskell Consultant
Well-Typed LLP,

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