I have some more info about this issue, just in case someone can lead
me to the light. I have changed my .config file, disabling hi-prec
timers and setting HZ to 1000. The problem seems to be gone until I
get a big load to the box. When I ping the board from my PC with a lot
of traffic, the hi-latency messages start again.
Thanks in advance!
Iratxo.
On Sun, Jun 14, 2009 at 5:28 PM, Iratxo Pichel
Ortiz<ipichel@xxxxxxxxxxxx> wrote:
> Hi there,
>
> I hope that someone in this list could help me trace down this issue I am
> seeing.
>
> I am using 2.6.30-rt16 RT Kernel on a IXP425 system. The system is running
> an experimental comm stack that has been working quite well with 2.6.26-rt2
> for a very long time (> 100days).
>
> When the system boots, every 180s aprox, I see this traces in the dmesg:
> 42949422.930000] NOHZ: local_softirq_pending 02
> [42949422.940000] NOHZ: local_softirq_pending 02
> [42949422.950000] NOHZ: local_softirq_pending 02
> [42949422.960000] ISR HIHG LATENCY 30073
> [42949596.920000] NOHZ: local_softirq_pending 02
> [42949596.930000] NOHZ: local_softirq_pending 02
> [42949596.940000] NOHZ: local_softirq_pending 02
> [42949596.950000] NOHZ: local_softirq_pending 02
> [42949596.960000] ISR HIHG LATENCY 40066
>
> The "ISR HIGH LATENCY" is small latency measurement that I have done in the
> ISR function of the driver. Hw is ticking the system every 2.5ms and the
> usual run-time of the ISR handler is well under 200us. Every aprox
> 180seconds, suddenly this run-time get as high as 50ms.
>
> It is very highly probable that the problem is inside my driver, because if
> I dont load the modules, this "NOHZ..." trace is not shown. Anyway, I would
> like to know if this "issue" is triggered by some known cause, or at least
> any idea where to start looking at.
>
> Please, CC me as I am not subscribed to the list.
>
> Thank you very much in advance and best regards!
>
> Iratxo.
>
>
> Another run:
> [ 96.950000] NOHZ: local_softirq_pending 02
> [ 96.960000] NOHZ: local_softirq_pending 02
> [ 96.970000] NOHZ: local_softirq_pending 02
> [ 97.000000] ISR HIGH LATENCY 50068
> [ 270.000000] ISR HIGH LATENCY 50048
> [ 463.000000] ISR HIGH LATENCY 50049
> [ 643.000000] ISR HIGH LATENCY 50047
>
> --
> Iratxo Pichel Ortiz
> Software Development Manager
>
> Albentia Systems S.A.
> http://www.albentia.com
>
> Tel: +34 914400567
> Cel: +34 663808405
> Fax: +34 914400569
>
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> Parque Tecnológico de Leganés
> Leganés (28918)
> Madrid
> Spain
>
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