Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> It will always remain orders of magnitude heavier than __thread >> variables which are a) inlined and b) should only need two memory >> accesses at worst. Moreover, it is clearly the future, while the >> importance of pthread_getspecific will decrease over the time. The >> __thread storage class is C99 standard (though its implementation >> remains a separate topic). > > You are exagerating a bit: pthread_getspecific is pretty efficient > already (from the few things that I have timed on ARM, it is the only > one which takes under the microsecond). That you will gain something > with __thread is not guaranteed by the C99 standard either: in fact the > implementation could use exactly the same functions.
As long as we do not loose anything (performance or portability), there is no point in sticking with pthread_getspecific. At least on x86 the advantage is easily visible (==no more function calls). That's also due to the lighter concept of __thread: it pushes the key resolution from runtime to compile/link-time. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
