Starting and joining a lot of threads slower on AMD systems compared to Intel systems

[Florent Guillaume]

On Mon, May 17, 2021 at 12:53 AM David Holmes <david.holmes at oracle.com>
wrote:

> On 16/05/2021 5:02 pm, Thomas Stüfe wrote:
> > On Sun, May 16, 2021 at 8:06 AM Thomas Stüfe <thomas.stuefe at gmail.com>
> > wrote:
> >
> >> The difference to J9 is annoying though.
> >>
> >> It just occurred to me that we have this handshake between creator
> thread
> >> and newborn thread. The creator thread waits for the newborn to be up
> and
> >> running, in order to avoid inconsistent thread states. Which requires
> the
> >> newborn to get at least some cycles, competing with all its siblings.
> >>
> >
> > Which interestingly we don't do for all platforms (not on AIX nor
> Windows).
> > Another reason to execute such tests on the same OS and hardware.
>
> As Linux/BSD/macOS can't start threads suspended we have to emulate that
> with this handshake. The reason this is needed is to ensure the newly
> created thread can't run to completion and delete itself before the
> creator has finished the initial interaction with it.
>

It seems that macOS has the Apple-specific POSIX_SPAWN_START_SUSPENDED to
do that.

Florent