Maybe it depends on the version of OS X being used? Maybe TLS works differently pre 10.8 or 10.9?
On Saturday, July 12, 2014, Johan Tibell <[email protected]> wrote: > I thought clang was slower than gcc because clang doesn't support thread > local variables (in some form we need) and therefore GC performance > suffered a lot on clang. > > > On Sat, Jul 12, 2014 at 9:27 PM, Mark Lentczner <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: > >> In building the OS X bindist for 7.8.3, I had to choose which of several >> ways to build it. In particular, I could build it with a newere Xcode, >> which uses clang, or an older Xcode which uses gcc. I decided to nofib >> benchmark the variations and see before I released. Here is what I found... >> >> I compared two candidate builds: >> >> - x86_64 architecture >> - targeted at OS X 10.7 and later >> - one built with Xcode 5.1 on 10.9, which uses clang >> - one built with Xcode 4.5 on 10.8, which uses gcc >> >> I installed both bindists, side-by-side on the same machine: a 10.9 >> machine, with Xcode 5.1, which uses clang. The machine is a MacMini, 2.5GHz >> Intel Core i5 (dual core, reports as 4 cpus). >> >> Summary: >> >> - clang build was always faster >> - non-threaded was -3.2% run-time >> - threaded was -7.3% run-time >> - clang's improvement in GC run-time was better than -10% >> - clang builds were significantly bigger >> >> You can find the details here: >> >> - analysis-Silver-10.9-gcc-vs-clang.html >> >> <http://www.ozonehouse.com/mark/platform/analysis-Silver-10.9-gcc-vs-clang.html> >> - analysis-Silver-10.9-gcc-vs-clang-threaded.html >> >> <http://www.ozonehouse.com/mark/platform/analysis-Silver-10.9-gcc-vs-clang-threaded.html> >> >> The only concern is that the binary sizes were significantly bigger: >> +230% - I haven't investigated more, but I'm wondering if nofib doesn't >> strip the binaries before measuring, and perhaps clang's debugging info is >> much greater? >> >> Next up... we are evaluating a bindist built with the HPC Mac OS X gcc >> compiler (based on gcc 4.9)... and preliminary results are looking even >> better! Stay tuned... >> >> - Mark >> >> >> _______________________________________________ >> ghc-devs mailing list >> [email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');> >> http://www.haskell.org/mailman/listinfo/ghc-devs >> >> >
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