Re: Moving sp_thread_pause, sp_thread_sleep to Core

From: Peter Dimov (pdimov_at_[hidden])
Date: 2023-06-02 17:01:05

Andrey Semashev wrote:
> >> #include <boost/smart_ptr/detail/sp_thread_pause.hpp>
> 
> There is a better implementation in Boost.Atomic:
> 
> https://github.com/boostorg/atomic/blob/2d45635e5b333f116030e3a779511d296c21f75f/include/boost/atomic/detail/pause.hpp

Indeed.

It's better in three ways: implementation for ARM, forceinline,
and noexcept.

I've applied these to sp_thread_pause (thanks) and in the process
submitted a GCC feature request

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110096

I've also applied the noexcept to the other two functions, which
lead me to discover an interesting issue with sp_thread_sleep:
nanosleep is a POSIX cancelation point, which means that it can
"throw":

https://github.com/boostorg/core/commit/e088fb89292bb301e69f4b35ba09defb4063f338

which exposed the need for the following fix:

https://github.com/boostorg/core/commit/23ef6d35316be0dfc4e110e701f2fccdeae94eec

Just thought these observations could be of interest to people here.