Messages in this thread | | | Date | Fri, 21 Jan 2005 12:25:53 -0800 | From | George Anzinger <> | Subject | Re: [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/
| |