Re: Linux 2.6.21: pmtmr losing time

From: Joerg Sommrey
Date: Mon Apr 30 2007 - 12:40:55 EST

On Mon, Apr 30, 2007 at 06:23:36PM +0200, Thomas Gleixner wrote:
> On Mon, 2007-04-30 at 14:52 +0200, Joerg Sommrey wrote:
> > Hi all,
> >
> > after switching to 2.6.21 the system clock sporadically loses time on my
> > box (i386, Athlon MP).
> > It's always around 4.68 seconds and happened 7 times in the last 12
> > hours. A simple calculation (2 ^ ACPI_PM_MASK / PMTMR_TICKS_PER_SEC =
> > 2 ^ 24 / 3579545 = 4.686968875) shows: There is almost exactly one
> > pmtmr-cycle missing. Could this be caused by a pmtmr-wrap when the
> > system is in a sleep state?
>
> Hmm, looks like. That's strange we don't sleep 4.68 seconds. Can you
> provide me the output of /proc/timer_list please ?
>
> tglx
>
>

Here it is. Maybe this problem is related to the usage of the
"experimental" amd76x_pm module?

-jo

Timer List Version: v0.3
HRTIMER_MAX_CLOCK_BASES: 2
now at 249154808025750 nsecs

cpu: 0
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1177701795305563440 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: <e4a79f00>, tick_sched_timer, S:01
# expires at 249154808417850 nsecs [in 392100 nsecs]
#1: <e4a79f00>, it_real_fn, S:01
# expires at 249154832599897 nsecs [in 24574147 nsecs]
#2: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249154937316640 nsecs [in 129290890 nsecs]
#3: <e4a79f00>, it_real_fn, S:01
# expires at 249154940604253 nsecs [in 132578503 nsecs]
#4: <e4a79f00>, it_real_fn, S:01
# expires at 249156991584989 nsecs [in 2183559239 nsecs]
#5: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249163930201148 nsecs [in 9122175398 nsecs]
#6: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249163930619465 nsecs [in 9122593715 nsecs]
#7: <e4a79f00>, it_real_fn, S:01
# expires at 249164018722673 nsecs [in 9210696923 nsecs]
#8: <e4a79f00>, it_real_fn, S:01
# expires at 249164018756764 nsecs [in 9210731014 nsecs]
#9: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249166140491719 nsecs [in 11332465969 nsecs]
#10: <e4a79f00>, it_real_fn, S:01
# expires at 249168890475020 nsecs [in 14082449270 nsecs]
#11: <e4a79f00>, it_real_fn, S:01
# expires at 249216937518155 nsecs [in 62129492405 nsecs]
#12: <e4a79f00>, it_real_fn, S:01
# expires at 249694958542841 nsecs [in 540150517091 nsecs]
#13: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 252071939585424 nsecs [in 2917131559674 nsecs]
#14: <e4a79f00>, it_real_fn, S:01
# expires at 277954353421786 nsecs [in 28799545396036 nsecs]
.expires_next : 249154808417850 nsecs
.hres_active : 1
.nr_events : 12571303
.nohz_mode : 2
.idle_tick : 249154808417850 nsecs
.tick_stopped : 0
.idle_jiffies : 74656449
.idle_calls : 31252991
.idle_sleeps : 18916982
.idle_entrytime : 249154806452801 nsecs
.idle_sleeptime : 202805663229475 nsecs
.last_jiffies : 74656449
.next_jiffies : 74656452
.idle_expires : 249154815084516 nsecs
jiffies: 74656449

cpu: 1
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1177701795305563440 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: <e4a79f00>, tick_sched_timer, S:01
# expires at 249154808417850 nsecs [in 392100 nsecs]
#1: <e4a79f00>, it_real_fn, S:01
# expires at 249154824005495 nsecs [in 15979745 nsecs]
#2: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249154876721584 nsecs [in 68695834 nsecs]
#3: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249154876724658 nsecs [in 68698908 nsecs]
#4: <e4a79f00>, it_real_fn, S:01
# expires at 249156991445550 nsecs [in 2183419800 nsecs]
#5: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249158033258177 nsecs [in 3225232427 nsecs]
#6: <e4a79f00>, it_real_fn, S:01
# expires at 249158937910855 nsecs [in 4129885105 nsecs]
#7: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249160645185907 nsecs [in 5837160157 nsecs]
#8: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 249288273241617 nsecs [in 133465215867 nsecs]
#9: <e4a79f00>, it_real_fn, S:01
# expires at 249688052597900 nsecs [in 533244572150 nsecs]
#10: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 250127175002655 nsecs [in 972366976905 nsecs]
#11: <e4a79f00>, hrtimer_wakeup, S:01
# expires at 252087970262178 nsecs [in 2933162236428 nsecs]
.expires_next : 249154808417850 nsecs
.hres_active : 1
.nr_events : 13107829
.nohz_mode : 2
.idle_tick : 249154805084517 nsecs
.tick_stopped : 0
.idle_jiffies : 74656448
.idle_calls : 27583722
.idle_sleeps : 11208166
.idle_entrytime : 249154805632934 nsecs
.idle_sleeptime : 197905845372598 nsecs
.last_jiffies : 74656449
.next_jiffies : 74656450
.idle_expires : 249154935084504 nsecs
jiffies: 74656449


Tick Device: mode: 1
Clock Event Device: pit
max_delta_ns: 27461866
min_delta_ns: 12571
mult: 5124677
shift: 32
mode: 3
next_event: 9223372036854775807 nsecs
set_next_event: pit_next_event
set_mode: init_pit_timer
event_handler: tick_handle_oneshot_broadcast
tick_broadcast_mask: 00000000
tick_broadcast_oneshot_mask: 00000000


Tick Device: mode: 1
Clock Event Device: lapic
max_delta_ns: 503300116
min_delta_ns: 1000
mult: 71585107
shift: 32
mode: 3
next_event: 249154808417850 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: 503300116
min_delta_ns: 1000
mult: 71585107
shift: 32
mode: 3
next_event: 249154808417850 nsecs
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: hrtimer_interrupt
-
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