Thomas Gleixner wrote:

On Fri, 2007-05-25 at 21:58 +0100, Rui Nuno Capela wrote:

quoted

Is there anything I can do better to help myself figuring out this
issue? As this is a  modern laptop such things like a serial console are
unavailable, but it would be nice to track things up over netconsole
perhaps?

I just need some bright and nice directions now ;) Hope someone finds
this worth of attention too. Meanwhile, I'll be happy with 2.6.21-rt1 :)

Can you boot with "hpet=disable" on the command line ?

Nope. It doesn't seem to have significant effect. Same time-bomb
behavior: after an indeterminate period of uptime, the systems stops
responding and cannot spawn new processes (current running ones still
live on, strange).

If that does not help, please provide the output of /proc/timer_list.

This is with my latest iteration:
  http://www.rncbc.org/datahub/config-2.6.21.1-rt8.0

Normal boot on which it behaves as badly as reported:
  http://www.rncbc.org/datahub/dmesg-2.6.21.1-rt8.0

# cat /proc/timer_list
Timer List Version: v0.3
HRTIMER_MAX_CLOCK_BASES: 2
now at 131736771907 nsecs

cpu: 0
 clock 0:
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1180213690448299114 nsecs
active timers:
 clock 1:
  .index:      1
  .resolution: 1 nsecs
  .get_time:   ktime_get
  .offset:     0 nsecs
active timers:
 #0: <ed7c4ef4>, tick_sched_timer, S:01
 # expires at 131737000000 nsecs [in 228093 nsecs]
 #1: <ed7c4ef4>, it_real_fn, S:01
 # expires at 131751277843 nsecs [in 14505936 nsecs]
 #2: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 131802703679 nsecs [in 65931772 nsecs]
 #3: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 131802705006 nsecs [in 65933099 nsecs]
 #4: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 132412838830 nsecs [in 676066923 nsecs]
 #5: <ed7c4ef4>, it_real_fn, S:01
 # expires at 137026607454 nsecs [in 5289835547 nsecs]
 #6: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 141381493725 nsecs [in 9644721818 nsecs]
 #7: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 170796028701 nsecs [in 39059256794 nsecs]
  .expires_next   : 131737000000 nsecs
  .hres_active    : 1
  .nr_events      : 40634
  .nohz_mode      : 2
  .idle_tick      : 131724000000 nsecs
  .tick_stopped   : 0
  .idle_jiffies   : 4294799020
  .idle_calls     : 178848
  .idle_sleeps    : 133212
  .idle_entrytime : 131736069830 nsecs
  .idle_sleeptime : 100895567465 nsecs
  .last_jiffies   : 4294799033
  .next_jiffies   : 4294799039
  .idle_expires   : 131736000000 nsecs
jiffies: 4294799033

cpu: 1
 clock 0:
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1180213690448299114 nsecs
active timers:
 clock 1:
  .index:      1
  .resolution: 1 nsecs
  .get_time:   ktime_get
  .offset:     0 nsecs
active timers:
 #0: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 131737067173 nsecs [in 295266 nsecs]
 #1: <ed7c4ef4>, tick_sched_timer, S:01
 # expires at 131737250000 nsecs [in 478093 nsecs]
 #2: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 139151071745 nsecs [in 7414299838 nsecs]
 #3: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 139151133755 nsecs [in 7414361848 nsecs]
 #4: <ed7c4ef4>, hrtimer_wakeup, S:01
 # expires at 139151154005 nsecs [in 7414382098 nsecs]
  .expires_next   : 131737067173 nsecs
  .hres_active    : 1
  .nr_events      : 31510
  .nohz_mode      : 2
  .idle_tick      : 131734250000 nsecs
  .tick_stopped   : 0
  .idle_jiffies   : 4294799030
  .idle_calls     : 151213
  .idle_sleeps    : 107018
  .idle_entrytime : 131735193036 nsecs
  .idle_sleeptime : 108256832194 nsecs
  .last_jiffies   : 4294799032
  .next_jiffies   : 4294799040
  .idle_expires   : 131743000000 nsecs
jiffies: 4294799033


Tick Device: mode:     1
Clock Event Device: hpet
 max_delta_ns:   2147483647
 min_delta_ns:   3352
 mult:           61496110
 shift:          32
 mode:           3
 next_event:     131737000000 nsecs
 set_next_event: hpet_legacy_next_event
 set_mode:       hpet_legacy_set_mode
 event_handler:  tick_handle_oneshot_broadcast
tick_broadcast_mask: 00000003
tick_broadcast_oneshot_mask: 00000001


Tick Device: mode:     1
Clock Event Device: lapic
 max_delta_ns:   806914928
 min_delta_ns:   1442
 mult:           44650051
 shift:          32
 mode:           1
 next_event:     131737000000 nsecs
 set_next_event: lapic_next_event
 set_mode:       lapic_timer_setup
 event_handler:  hrtimer_interrupt

Tick Device: mode:     1
Clock Event Device: lapic
 max_delta_ns:   806914928
 min_delta_ns:   1442
 mult:           44650051
 shift:          32
 mode:           3
 next_event:     131737067173 nsecs
 set_next_event: lapic_next_event
 set_mode:       lapic_timer_setup
 event_handler:  hrtimer_interrupt
--


Alternate boot with hpet=disabled as suggested, but no better results:
  http://www.rncbc.org/datahub/dmesg-2.6.21.1-rt8.0-hpet_disabled

# cat /proc/timer_list
Timer List Version: v0.3
HRTIMER_MAX_CLOCK_BASES: 2
now at 269529706096 nsecs

cpu: 0
 clock 0:
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1180214106093436428 nsecs
active timers:
 clock 1:
  .index:      1
  .resolution: 1 nsecs
  .get_time:   ktime_get
  .offset:     0 nsecs
active timers:
 #0: <ed2a2ef4>, tick_sched_timer, S:01
 # expires at 269530000000 nsecs [in 293904 nsecs]
 #1: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 269554568320 nsecs [in 24862224 nsecs]
 #2: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 269585566924 nsecs [in 55860828 nsecs]
 #3: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 269822782823 nsecs [in 293076727 nsecs]
 #4: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 272726158017 nsecs [in 3196451921 nsecs]
 #5: <ed2a2ef4>, it_real_fn, S:01
 # expires at 278007767018 nsecs [in 8478060922 nsecs]
 #6: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 283716431029 nsecs [in 14186724933 nsecs]
 #7: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 283716456168 nsecs [in 14186750072 nsecs]
 #8: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 295789281627 nsecs [in 26259575531 nsecs]
  .expires_next   : 269530000000 nsecs
  .hres_active    : 1
  .nr_events      : 63228
  .nohz_mode      : 2
  .idle_tick      : 269527000000 nsecs
  .tick_stopped   : 0
  .idle_jiffies   : 4294936823
  .idle_calls     : 217590
  .idle_sleeps    : 168323
  .idle_entrytime : 269528785728 nsecs
  .idle_sleeptime : 230915526366 nsecs
  .last_jiffies   : 4294936825
  .next_jiffies   : 4294936840
  .idle_expires   : 269543000000 nsecs
jiffies: 4294936826

cpu: 1
 clock 0:
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1180214106093436428 nsecs
active timers:
 clock 1:
  .index:      1
  .resolution: 1 nsecs
  .get_time:   ktime_get
  .offset:     0 nsecs
active timers:
 #0: <ed2a2ef4>, tick_sched_timer, S:01
 # expires at 269530250000 nsecs [in 543904 nsecs]
 #1: <ed2a2ef4>, it_real_fn, S:01
 # expires at 269546379364 nsecs [in 16673268 nsecs]
 #2: <ed2a2ef4>, hrtimer_wakeup, S:01
 # expires at 283723356553 nsecs [in 14193650457 nsecs]
  .expires_next   : 269530250000 nsecs
  .hres_active    : 1
  .nr_events      : 64947
  .nohz_mode      : 2
  .idle_tick      : 269527250000 nsecs
  .tick_stopped   : 0
  .idle_jiffies   : 4294936824
  .idle_calls     : 172684
  .idle_sleeps    : 111081
  .idle_entrytime : 269529298565 nsecs
  .idle_sleeptime : 234502295072 nsecs
  .last_jiffies   : 4294936826
  .next_jiffies   : 4294936833
  .idle_expires   : 269536000000 nsecs
jiffies: 4294936826


Tick Device: mode:     1
Clock Event Device: pit
 max_delta_ns:   27461866
 min_delta_ns:   12571
 mult:           5124677
 shift:          32
 mode:           3
 next_event:     269530250000 nsecs
 set_next_event: pit_next_event
 set_mode:       init_pit_timer
 event_handler:  tick_handle_oneshot_broadcast
tick_broadcast_mask: 00000003
tick_broadcast_oneshot_mask: 00000002


Tick Device: mode:     1
Clock Event Device: lapic
 max_delta_ns:   807031401
 min_delta_ns:   1443
 mult:           44643607
 shift:          32
 mode:           3
 next_event:     269530000000 nsecs
 set_next_event: lapic_next_event
 set_mode:       lapic_timer_setup
 event_handler:  hrtimer_interrupt

Tick Device: mode:     1
Clock Event Device: lapic
 max_delta_ns:   807031401
 min_delta_ns:   1443
 mult:           44643607
 shift:          32
 mode:           1
 next_event:     269530250000 nsecs
 set_next_event: lapic_next_event
 set_mode:       lapic_timer_setup
 event_handler:  hrtimer_interrupt
--

Thanks for the hints.

Cheers.
-- 
rncbc aka Rui Nuno Capela
rncbc@rncbc.org