On 2010-10-13 07:17, Walter Bright wrote:
Denis Koroskin wrote:
Either way, it needs some language support, because currently TLS
implemented on compiler level rather than library level. I proposed
this change in past, but no one responded.
Using TLS needs operating system support, and there's special linker
support for it and the compiler has to generate TLS references in
certain ways in order for it to work.
There is no such support in OSX for TLS, and it is done manually by the
library. However, TLS access is 10 times slower than on Linux/Windows.
Without doing TLS in the operating system standard way, you tend to get
hosed if you link with a shared library/DLL that has TLS.
I don't know how you have implemented TLS on Mac OS X but it does
support TLS via the Posix API pthreads. This is the only page from
Apple's documentation I could find for now (I'm certain I've seen a
better page)
http://developer.apple.com/macosx/multithreadedprogramming.html .
According to these:
http://lifecs.likai.org/2010/05/mac-os-x-thread-local-storage.html and
http://lists.apple.com/archives/darwin-dev/2005/Sep/msg00005.html the
implementation of TLS in the Posix API on Mac OS X should be as fast as
the EFL implementation. As the blog post mentions, there is an inline
version of pthread_getspecific. I also have to add that I have no idea
if the pthreads can be used to implement TLS in the compiler.
--
/Jacob Carlborg
