Re: Cygwin: Implement sched_[gs]etaffinity() commit breaks RTEMS port

Corinna Vinschen <[email protected]> Fri, 28 Jun 2019 16:14:14 +0200
Newsgroups	gmane.comp.lib.newlib
Message-ID	<[email protected]>
On Jun 28 03:17, Mark Geisert wrote:
> On Fri, 28 Jun 2019, Sebastian Huber wrote:
> > On 28/06/2019 10:48, Mark Geisert wrote:
> > > On Thu, 27 Jun 2019, Corinna Vinschen wrote:
> > > > On Jun 27 08:28, Sebastian Huber wrote:
> > > > > On 26/06/2019 15:12, Corinna Vinschen wrote:
> > > > > > On Jun 26 13:05, Sebastian Huber wrote:
> > > > > > > On 26/06/2019 11:37, Corinna Vinschen wrote:
> > > > > > > > On Jun 26 10:24, Sebastian Huber wrote:
> > > > > > > > > Hello,
> > > > > > > > > 
> > > > > > > > > the following commit:
> > > > > > > > > 
> > > > > > > > > commit 641ecb07533e85211b6abce334c85967f3f90209
> > > > > > > > > Author: Mark Geisert<[email protected]>
> > > > > > > > > Date:   Sun Jun 23 14:51:06 2019 -0700
> > > > > > > > > 
> > > > > > > > >       Cygwin: Implement sched_[gs]etaffinity()
> > > > > > > > > [...]
> > > > > > > > > breaks the RTEMS port:
> > > > > > > > > [...]
> > > > > > > > Looks like Cygwin has to define its own sys/cpuset.h included via
> > > > > > > > sys/_pthreadtypes.h.
> > > > > > > 
> > > [...]
> > > Hi folks,
> > > I was trying to minimize update scope while implementing the
> > > affinity calls from Linux for Cygwin.  I noticed that taskset(1),
> > > from the util-linux package, supplies its own CPU_SET implementation
> > > (copied from glibc) so I decided to not supply one for Cygwin but
> > > let taskset use its own.  I felt we could add CPU_SET to Cygwin when
> > > necessary, later.
> > > 
> > > The macro #defines I added to sched.h are those needed by Linux
> > > CPU_SET regardless of how it gets defined.  I worry about trying to
> > > use a FreeBSD based CPU_SET -- just from unfamiliarity.
> > 
> > The RTEMS <sys/cpuset.h> implements the Linux and FreeBSD APIs. In case
> > of conflict (and there are conflicts, the libc developers should talk
> > more with each other) we choose the Linux variant.
> 
> O.K. Thank you for the background.
> 
> > > [...]
> > > I don't see how the include linkage through _pthreadtypes.h works
> > > though. How does a user app including <sched.h> get <sys/cpuset.h>
> > > pulled in?
> > 
> > It is included via <sys/types.h> -> <sys/_pthreadtypes.h> -> <sys/cpuset.h>.
> 
> Great!  Thank you Sebastian.
> 
> Corinna, I'm able to build Cygwin 64- and 32-bit with your updates, and to
> build util-linux as well.  I have a resulting working taskset executable.
> 
> It was not necessary to implement the CPU_SET functionality via any of the
> possible ways because taskset supplies its own if it can't find one.
> 
> We can call it a day, with review and release of the current patch state.
> If you think it's worthwhile to implement CPU_SET on Cygwin now, rather than
> later, I can look into it but it's not strictly necessary at this time.
> 
> Let me know what you think when you have a chance.

I'll push my patch, but it would be nice if we could provide the
definitions from http://man7.org/linux/man-pages/man3/CPU_SET.3.html as
well.


Thanks,
Corinna
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