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From "Nathan Beyer" <nbe...@gmail.com>
Subject Re: [drlvm] thread local storage in open/hythread.h
Date Mon, 31 Mar 2008 14:00:11 GMT
On Mon, Mar 31, 2008 at 7:45 AM, Francis ANDRE <francis.andre@easynet.fr> wrote:
>  >> Do you have any suggestions or preferences about a particular TLS
>   >> approach? I'm all for fast, but I tend to lean towards a consistent
>   >> (single) clean approach, even it it's not the fastest approach.
>
>  What would you think about using the zthread package as general rule and using
>  optimal hand coded part for optimization??
>  http://zthread.sourceforge.net/
>
>  Francis

I'm not familiar with that project, so I can't really comment. What
would be the advantages of using it?

-Nathan

>
>  Pavel Rebriy a écrit :
>
>
> > Nathan,
>  >
>  > TLS access is a performance critical function, that why unified (single,
>  > clean) approach could have 20-30% of performance degradation on some
>  > benchmarks.
>  >
>  > On 31/03/2008, Nathan Beyer <nbeyer@gmail.com> wrote:
>  >> On Sun, Mar 30, 2008 at 4:41 PM, Gregory Shimansky
>  >> <gshimansky@apache.org> wrote:
>  >>> On 29 марта 2008 Nathan Beyer wrote:
>  >>>  > In open/hythread.h there is the following bit of code.
>  >>>  >
>  >>>  > #ifdef PLATFORM_POSIX
>  >>>  > extern __thread hythread_t tm_self_tls;
>  >>>  > #else
>  >>>  > extern __declspec(thread) hythread_t tm_self_tls;
>  >>>  > #endif //PLATFORM_POSIX
>  >>>  >
>  >>>  >
>  >>>  > hy_inline hythread_t VMCALL hythread_self() {
>  >>>  >     return tm_self_tls;
>  >>>  > }
>  >>>  >
>  >>>  > From what I know at the moment, the use of '__thread' isn't a POSIX
>  >>>  > standard, but rather a gcc extension and '__declspec(thread)' is
a
>  >>>  > MSVC thing, so the check isn't quite correct. Neither of these works
>  >>>  > on MacOS X and from what I've been able to gather, it shouldn't work
>  >>>  > on FreeBSD, but I can't confirm that. In any case, I was looking
at
>  >>>  > implementing this for MacOSX and FreeBSD using pthread_key_t. It
>  >> seems
>  >>>  > like that could be used for other (all?) platforms as well. Any
>  >>>  > thoughts on that?
>  >>>
>  >>>  AFAIK there are plenty of different implementation for getting TLS in
>  >> DRLVM's
>  >>>  implementation of hythread. There are fast ways like those you've
>  >> mentioned,
>  >>>  slow ways using APR and pthread and very fast ways using inline
>  >> assembly.
>  >>>  All of them are quite messed up right now and need some cleaning. The
>  >> mess is
>  >>>  with different defines that rule the whole stuff - it is not always
>  >> clear
>  >>>  which define set is used for a particular implementation on a given
>  >> platform.
>  >>
>  >>
>  >> I would agree that the defines are a bit of a mess or at least seem
>  >> like it at times.
>  >>
>  >> Do you have any suggestions or preferences about a particular TLS
>  >> approach? I'm all for fast, but I tend to lean towards a consistent
>  >> (single) clean approach, even it it's not the fastest approach.
>  >>
>  >>>  --
>  >>>  Gregory
>  >>>
>  >
>  >
>  >
>
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