lkml.org 
[lkml]   [2005]   [Jan]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] dynamic tick patch
Zwane Mwaikambo wrote:
> On Fri, 21 Jan 2005, Tony Lindgren wrote:
>
>
>>>This doesn't seem to cover the local APIC timer, what do you do about the
>>>1kHz tick which it's programmed to do?
>>
>>Sorry for the delay in replaying. Thanks for pointing that out, I
>>don't know yet what to do with the local APIC timer. Have to look at
>>more.
>
>
> Pavel does your test system have a Local APIC? If so that may also explain
> why you didn't see a difference.
>
> Tony, something like the following for oneshot should work, untested of
> course. Perhaps you could use that for the wakeup interrupt instead?
>
> void setup_oneshot_apic_timer(unsigned int count)
> {
> unsigned int lvtt, tmp_value;
> unsigned long flags;
>
> count *= calibration_result;
> local_irq_save(flags);
> lvtt = ~APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
> apic_write_around(APIC_LVTT, lvtt);
> tmp_value = apic_read(APIC_TDCR);
> apic_write_around(APIC_TDCR, (tmp_value
> & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
> | APIC_TDR_DIV_16);
>
> apic_write_around(APIC_TMICT, count/APIC_DIVISOR);
> local_irq_restore(flags);
> }

The VST patch on sourceforge (http://sourceforge.net/projects/high-res-timers/)
uses the local apic timer to do the wake up. This is the same timer that is
used for the High Res work.

--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/

-
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: 2005-03-22 14:09    [W:0.091 / U:0.320 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site