Messages in this thread | | | Date | Fri, 01 May 2015 10:17:02 +0200 | From | Mason <> | Subject | Re: High-resolution timers not supported when using smp_twd |
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Hello John,
On 30/04/2015 18:42, John Stultz wrote:
> On Thu, Apr 30, 2015 at 5:46 AM, Mason wrote: > >> I wanted to enable high-resolution timers on this Cortex A9 system, >> but it seems there is more to it than just enabling >> >> CONFIG_HIGH_RES_TIMERS=y >> >> (The system is limited to jiffy resolution.) > > You might make sure you've got a HRT enabled clocksource installed? > > You might check > /sys/devices/system/clocksource/clocksource0/current_clocksource ?
Thanks for the suggestion, I will check on Monday.
The clocksource is a constant 27 MHz 32-bit counter.
It seems the problem comes from the clockevent source, which is marked CLOCK_EVT_FEAT_C3STOP. If I remove that flag, then hrtimers are enabled; but the flag is there for a good reason, I assume.
I will resend my message to the LAKML on Monday.
Regards.
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