Date: Fri, 3 May 2019 02:24:05 -0700 From: Mark Millard <marklmi@yahoo.com> To: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>, Justin Hibbits <chmeeedalf@gmail.com> Subject: 970MP PowerMac G5s: What some basic printf's show about vt_upgrade and fhanew_init hang-ups Message-ID: <EEF5564B-F155-4A8E-9871-8465C94E5E6A@yahoo.com>
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[Note: I still have Justin's requested loop change, my
isync additions, and my libc string compare code
change in what I'm working with for head -r347003 .
Also DELAY has the 2 priority-change calls commented
out, per the prior list submittal about controlling
cpu_mp_unleash hang-up behavior.]
In /mnt/usr/src/sys/dev/vt/vt_core.c 's vt_upgrade, when it hangs up,
the first printf below shows but the second one does not:
callout_init_mtx(&vd->vd_timer, &vd->vd_lock, 0);
printf("vt_upgrade after callout_init_mtx / before sequence leading to =
callout_reset\n");
/*
* Start timer when everything ready.
* Note that the operations here are purposefully =
ordered.
* We need to ensure vd_timer_armed is non-zero before =
we set
* the VDF_ASYNC flag. That prevents this function from
* racing with vt_resume_flush_timer() to update the
* callout structure.
*/
atomic_add_acq_int(&vd->vd_timer_armed, 1);
vd->vd_flags |=3D VDF_ASYNC;
callout_reset(&vd->vd_timer, hz / VT_TIMERFREQ, =
vt_timer, vd);
printf("vt_upgrade after callout_reset\n");
In /mnt/usr/src/sys/fs/nfsserver/nfs_fha_new.c 's fhanew_init, when it
hangs up, the first printf below shows but the second one does not:
sysctl_ctx_init(&softc->sysctl_ctx);
printf("fhanew_init: after sysctl_ctx_init / before SYSCTL_ADD_NODE\n");
softc->sysctl_tree =3D SYSCTL_ADD_NODE(&softc->sysctl_ctx,
SYSCTL_STATIC_CHILDREN(_vfs_nfsd), OID_AUTO, "fha", =
CTLFLAG_RD,
0, "NFS File Handle Affinity (FHA)");
printf("fhanew_init: after SYSCTL_ADD_NODE\n");
Ignoring cpu_mp_unleash, I've not run into other hang-up points
in these or other routines. (cpu_mp_unleash has its own list
submittal about controlling its hang-up behavior.)
At this point I've no clue about controlling the behavior of
the above 2 hang-up points. I've no evidence about if
slb-misses are involved vs. not.
I no longer have the other printf's that I'd added to the 2 routines,
based on only seeing these hang-up points in each of the two (so
far).
=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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