lkml.org 
[lkml]   [2013]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Enable arm_global_timer for Zynq brakes boot
Forget this. It's trash. I had to migrate some stuff around due to some
quota issues and missed to update a few scripts. Sorry, I'll rerun this
test.

Sören

On Tue, Jul 30, 2013 at 03:14:43PM -0700, Sören Brinkmann wrote:
> On Tue, Jul 30, 2013 at 10:47:15AM +0200, Daniel Lezcano wrote:
> > On 07/30/2013 02:03 AM, Sören Brinkmann wrote:
> > > Hi Daniel,
> > >
> > > On Mon, Jul 29, 2013 at 02:51:49PM +0200, Daniel Lezcano wrote:
> > > (snip)
> > >>
> > >> the CPUIDLE_FLAG_TIMER_STOP flag tells the cpuidle framework the local
> > >> timer will be stopped when entering to the idle state. In this case, the
> > >> cpuidle framework will call clockevents_notify(ENTER) and switches to a
> > >> broadcast timer and will call clockevents_notify(EXIT) when exiting the
> > >> idle state, switching the local timer back in use.
> > >
> > > I've been thinking about this, trying to understand how this makes my
> > > boot attempts on Zynq hang. IIUC, the wrongly provided TIMER_STOP flag
> > > would make the timer core switch to a broadcast device even though it
> > > wouldn't be necessary. But shouldn't it still work? It sounds like we do
> > > something useless, but nothing wrong in a sense that it should result in
> > > breakage. I guess I'm missing something obvious. This timer system will
> > > always remain a mystery to me.
> > >
> > > Actually this more or less leads to the question: What is this
> > > 'broadcast timer'. I guess that is some clockevent device which is
> > > common to all cores? (that would be the cadence_ttc for Zynq). Is the
> > > hang pointing to some issue with that driver?
> >
> > If you look at the /proc/timer_list, which timer is used for broadcasting ?
>
> In case of a vanilla kernel and with my patches for enabling the global
> timer (I removed the wrongly set flag from the C2 state + adding the DT
> fragment to use the GT), this is what I see (full output from timer_list
> attached):
> Tick Device: mode: 1
> Broadcast device
> Clock Event Device: xttcps_clockevent
>
> And the local timer seems to be the arm twd timer (also in both cases).
>
> I don't think I can gather this information for the actual broken case,
> but AFAIK, there shouldn't be any other timer be capable of this for
> Zynq.
>
> Sören
>

> Timer List Version: v0.7
> HRTIMER_MAX_CLOCK_BASES: 3
> now at 76779317814 nsecs
>
> cpu: 0
> clock 0:
> .base: c14a0c90
> .index: 0
> .resolution: 1 nsecs
> .get_time: ktime_get
> .offset: 0 nsecs
> active timers:
> #0: <c14a2b50>, menu_hrtimer_notify, S:01, hrtimer_start, swapper/0/0
> # expires at 76779328789-76779328789 nsecs [in 10975 to 10975 nsecs]
> #1: <c14a0dd8>, tick_sched_timer, S:01, hrtimer_start, swapper/0/0
> # expires at 76800000000-76800000000 nsecs [in 20682186 to 20682186 nsecs]
> #2: <ed956e40>, timerfd_tmrproc, S:01, hrtimer_start, systemd/1
> # expires at 93249172026-93249172026 nsecs [in 16469854212 to 16469854212 nsecs]
> #3: <ed956c00>, timerfd_tmrproc, S:01, hrtimer_start, systemd/1
> # expires at 900000055806-900000055806 nsecs [in 823220737992 to 823220737992 nsecs]
> clock 1:
> .base: c14a0cc8
> .index: 1
> .resolution: 1 nsecs
> .get_time: ktime_get_real
> .offset: 975789465870609368 nsecs
> active timers:
> clock 2:
> .base: c14a0d00
> .index: 2
> .resolution: 1 nsecs
> .get_time: ktime_get_boottime
> .offset: 0 nsecs
> active timers:
> .expires_next : 76779492678 nsecs
> .hres_active : 1
> .nr_events : 2449
> .nr_retries : 66
> .nr_hangs : 0
> .max_hang_time : 0 nsecs
> .nohz_mode : 2
> .last_tick : 76780000000 nsecs
> .tick_stopped : 1
> .idle_jiffies : 4294944973
> .idle_calls : 3114
> .idle_sleeps : 981
> .idle_entrytime : 76779354678 nsecs
> .idle_waketime : 76779336246 nsecs
> .idle_exittime : 76769862116 nsecs
> .idle_sleeptime : 70735903990 nsecs
> .iowait_sleeptime: 18432 nsecs
> .last_jiffies : 4294944973
> .next_jiffies : 4294944976
> .idle_expires : 76800000000 nsecs
> jiffies: 4294944973
>
> cpu: 1
> clock 0:
> .base: c14a9c90
> .index: 0
> .resolution: 1 nsecs
> .get_time: ktime_get
> .offset: 0 nsecs
> active timers:
> #0: <c14a9dd8>, tick_sched_timer, S:01, hrtimer_start_range_ns, swapper/1/0
> # expires at 76780000000-76780000000 nsecs [in 682186 to 682186 nsecs]
> clock 1:
> .base: c14a9cc8
> .index: 1
> .resolution: 1 nsecs
> .get_time: ktime_get_real
> .offset: 975789465870609368 nsecs
> active timers:
> clock 2:
> .base: c14a9d00
> .index: 2
> .resolution: 1 nsecs
> .get_time: ktime_get_boottime
> .offset: 0 nsecs
> active timers:
> .expires_next : 76780000000 nsecs
> .hres_active : 1
> .nr_events : 2257
> .nr_retries : 61
> .nr_hangs : 0
> .max_hang_time : 0 nsecs
> .nohz_mode : 2
> .last_tick : 76700000000 nsecs
> .tick_stopped : 0
> .idle_jiffies : 4294944965
> .idle_calls : 2998
> .idle_sleeps : 444
> .idle_entrytime : 76771944950 nsecs
> .idle_waketime : 76768498136 nsecs
> .idle_exittime : 76768498136 nsecs
> .idle_sleeptime : 72124544054 nsecs
> .iowait_sleeptime: 4276262 nsecs
> .last_jiffies : 4294944973
> .next_jiffies : 4294944974
> .idle_expires : 78880000000 nsecs
> jiffies: 4294944973
>
>
> Tick Device: mode: 1
> Broadcast device
> Clock Event Device: xttcps_clockevent
> max_delta_ns: 1207932479
> min_delta_ns: 18432
> mult: 233015
> shift: 32
> mode: 1
> next_event: 9223372036854775807 nsecs
> set_next_event: xttcps_set_next_event
> set_mode: xttcps_set_mode
> event_handler: tick_handle_oneshot_broadcast
> retries: 0
> tick_broadcast_mask: 00000000
> tick_broadcast_oneshot_mask: 00000000
>
>
> Tick Device: mode: 1
> Per CPU device: 0
> Clock Event Device: local_timer
> max_delta_ns: 12884902005
> min_delta_ns: 1000
> mult: 715827876
> shift: 31
> mode: 3
> next_event: 76800000000 nsecs
> set_next_event: twd_set_next_event
> set_mode: twd_set_mode
> event_handler: hrtimer_interrupt
> retries: 0
>
> Tick Device: mode: 1
> Per CPU device: 1
> Clock Event Device: local_timer
> max_delta_ns: 12884902005
> min_delta_ns: 1000
> mult: 715827876
> shift: 31
> mode: 3
> next_event: 76780000000 nsecs
> set_next_event: twd_set_next_event
> set_mode: twd_set_mode
> event_handler: hrtimer_interrupt
> retries: 0
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2013-07-31 00:41    [W:0.094 / U:0.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site