[D-runtime] About a suspension comment in core.thread

[Alex Rønne Petersen]

Hey,

In core.thread:suspend(), there is this comment:

                // NOTE: It's really not ideal to wait for each thread to
                //       signal individually -- rather, it would be better to
                //       suspend them all and wait once at the end.  However,
                //       semaphores don't really work this way, and the obvious
                //       alternative (looping on an atomic suspend count)
                //       requires either the atomic module (which only works on
                //       x86) or other specialized functionality.  It would
                //       also be possible to simply loop on sem_wait at the
                //       end, but I'm not convinced that this would be much
                //       faster than the current approach.
                sem_wait( &suspendCount );

Has this turned out to be a performance problem in practice? These
days, core.atomic works everywhere (LDC and GDC use intrinsics), so
using that should be trivial. But I don't want to bother with this if
no one has had performance problems with this suspension strategy
anyway.

Regards,
Alex