Date: Fri, 27 Oct 2006 13:49:22 +0400 From: Ruslan Ermilov <ru@FreeBSD.org> To: Ivan Voras <ivoras@fer.hr> Cc: freebsd-current@FreeBSD.org Subject: Re: KSE, libpthread & libthr: almost newbie question Message-ID: <20061027094922.GC6613@rambler-co.ru> In-Reply-To: <ehshjl$dsp$1@sea.gmane.org> References: <917908193.20061027102647@serebryakov.spb.ru> <ehshjl$dsp$1@sea.gmane.org>
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On Fri, Oct 27, 2006 at 10:56:21AM +0200, Ivan Voras wrote:
> Lev Serebryakov wrote:
> >Hello ,
> >
> > I've was sure, that both libpthread and libthr use KSE to make=20
> > multithreading. They use KSE in different ways: libpthread uses N:M=
=20
> > model and libthr uses 1:1 model, but bot use KSE to work.
> > How will be possible to use these libraries (read: multithreaded=20
> > programs) when KSE will be optional, on kernel without KSE?!
>=20
> Yes, isn't KSE by definition "that thing that is scheduled in the kernel"?
>=20
KSE =3D=3D N:M threading
A 1:1 threading (libthr) is much simpler than N:M threading (libpthread),
and thus doesn't require KSE support in the kernel; see kse(2) manpage
for details. Without the KSE option in the kernel, all kse(2) syscalls
will return EOPNOTSUPP, and a lot of code becomes redundant.
: /*
: * Initialize global thread allocation resources.
: */
: void
: threadinit(void)
: {
:=20
: mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
: tid_unrhdr =3D new_unrhdr(PID_MAX + 1, INT_MAX, &tid_lock);
:=20
: thread_zone =3D uma_zcreate("THREAD", sched_sizeof_thread(),
: thread_ctor, thread_dtor, thread_init, thread_fini,
: UMA_ALIGN_CACHE, 0);
: #ifdef KSE
: ksegrp_zone =3D uma_zcreate("KSEGRP", sched_sizeof_ksegrp(),
: ksegrp_ctor, NULL, NULL, NULL,
: UMA_ALIGN_CACHE, 0);
: kseinit(); /* set up kse specific stuff e.g. upcall zone*/
: #endif
: }
Cheers,
--=20
Ruslan Ermilov
ru@FreeBSD.org
FreeBSD committer
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