On 01/09/2010 02:23 PM, Stefan Strasser wrote:
Am Saturday 09 January 2010 13:22:23 schrieb Andrey Semashev:
I see. but while that is a good reason to have a std::map (or unordered_map) in boost, I still don't get why you can't use thread local storage for saving the pointer to the map (i.e. the result of get_current_thread_data()).
I can't say I understand all the details of the current implementation, but in case pthread_setspecific etc. needs to be kept for some reason related to construction/destruction, it seems to me at the very least the result of get_current_thread_data() could be cached in a thread-local variable.
The pointer to the thread-specific data is stored in TLS, last time I checked. And there's no difference in terms of performance in how you store the pointer - via __thread specifier or by manually calling pthread APIs. In case of __thread the compiler will generate the necessary calls to pthread for you, that all you win, AFAIU.
that would speed up thread_specific_ptr::get() 5-fold according to my profiling.
Hmm, that's unexpected. Could you post a patch to test with?