system priorities

[Daniel Eischen]

On Sat, 1 May 2004, Petri Helenius wrote:

> Daniel Eischen wrote:
>=20
> >>This sounds like a bug. Could it change the KSEG which called the rtpri=
o=20
> >>so there would be some deterministic behaviour to the rtprio if used in=
=20
> >>threaded program? So I take it from this that rtprio is also broken for=
=20
> >>libthr?
> >>   =20
> >>
> >
> >Yes.
> >
> > =20
> >
> Can and should it be fixed?

Index: kern/kern_resource.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /opt/FreeBSD/cvs/src/sys/kern/kern_resource.c,v
retrieving revision 1.136
diff -u -r1.136 kern_resource.c
--- kern/kern_resource.c=0910 Apr 2004 11:08:16 -0000=091.136
+++ kern/kern_resource.c=091 May 2004 14:00:37 -0000
@@ -318,6 +318,7 @@
 {
 =09struct proc *curp;
 =09register struct proc *p;
+=09struct ksegrp *kg;
 =09struct rtprio rtp;
 =09int cierror, error;
=20
@@ -328,6 +329,7 @@
 =09=09cierror =3D 0;
=20
 =09curp =3D td->td_proc;
+=09kg =3D td->td_ksegrp;
 =09if (uap->pid =3D=3D 0) {
 =09=09p =3D curp;
 =09=09PROC_LOCK(p);
@@ -342,7 +344,7 @@
 =09=09if ((error =3D p_cansee(td, p)))
 =09=09=09break;
 =09=09mtx_lock_spin(&sched_lock);
-=09=09pri_to_rtp(FIRST_KSEGRP_IN_PROC(p), &rtp);
+=09=09pri_to_rtp(kg, &rtp);
 =09=09mtx_unlock_spin(&sched_lock);
 =09=09PROC_UNLOCK(p);
 =09=09return (copyout(&rtp, uap->rtp, sizeof(struct rtprio)));
@@ -373,7 +375,7 @@
 =09=09=09}
 =09=09}
 =09=09mtx_lock_spin(&sched_lock);
-=09=09error =3D rtp_to_pri(&rtp, FIRST_KSEGRP_IN_PROC(p));
+=09=09error =3D rtp_to_pri(&rtp, kg);
 =09=09mtx_unlock_spin(&sched_lock);
 =09=09break;
 =09default:
Index: kern/kern_thread.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /opt/FreeBSD/cvs/src/sys/kern/kern_thread.c,v
retrieving revision 1.176
diff -u -r1.176 kern_thread.c
--- kern/kern_thread.c=0928 Apr 2004 20:36:53 -0000=091.176
+++ kern/kern_thread.c=091 May 2004 14:06:50 -0000
@@ -337,7 +337,7 @@
 =09kg->kg_numupcalls =3D 0;
 =09/* link it in now that it's consistent */
 =09p->p_numksegrps++;
-=09TAILQ_INSERT_HEAD(&p->p_ksegrps, kg, kg_ksegrp);
+=09TAILQ_INSERT_TAIL(&p->p_ksegrps, kg, kg_ksegrp);
 }
=20
 void

> >
> >The Solaris priocntl() lets you set/get:
> >
> >     P_LWPID
> >           The id argument is an LWP ID.  The  priocntl  function
> >           applies  to  the  LWP with the specified ID within the
> >           calling process.
> >
> >   =20
> >
> Where would I get the "P_LWPID"? I=B4m not sure it's a good idea to expos=
e=20
> the kse structure to an application using pthreads.

There would be a way to get it, but you needn't if you
use P_MYID.  Solaris has _lwp_self().  One of the other
things on my wish list is to be able to bind (soft
affinity) KSEs to processors.

--=20
Dan Eischen