On Fri, 4 Oct 2024 at 04:35, Gaius Mulley wrote:
Unfortunately, Gaius has chosen to use the GNU portable threads library (aka pth) to implement
coroutines in GM2. The pth library is built on top of kernel threads, it merely gives you a user interface
that looks like user level threads, but the threads are actually kernel threads, which means there is no scalability gain.
gm2 moved away from using GNU Portable Threads circa 2018. It
now uses the gnu threading library (found in the gcc sources) not to be
confused with GNU Portable Threads. Around 2018 this was one of the
prerequisite changes required to get gm2 into the GCC tree.
I think most (if not all) front ends use this library (C++, go,
etc) and it implements the user level threads as you describe above
(with all the advantages of simplicity and portability)
OK, but does this library provide *actual* user level threads, not just an interface that mimics them?
It is always possible to wrap a simpler user interface around any concurrency library, but the scalability advantage of user level threads cannot be gained this way if the underlying library does not use actual user level threading.
regards
benjamin