From: Olof Johansson <olof@lixom•net>
To: Paul Mackerras <paulus@samba•org>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [RFC/PATCH 2/2] Generic clockevents and no-idle-HZ for PowerPC
Date: Thu, 6 Sep 2007 14:15:16 -0500 [thread overview]
Message-ID: <20070906191516.GA20090@lixom.net> (raw)
In-Reply-To: <18144.4702.673658.336384@cargo.ozlabs.ibm.com>
Hi,
Nice! I've been looking forward to these patches. Should help keep power
consumption down on machines with powersavings support for idle.
On Fri, Sep 07, 2007 at 12:44:46AM +1000, Paul Mackerras wrote:
> @@ -749,6 +805,8 @@ void __init clocksource_init(void)
> printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
> clocksource_timebase.name,
> clocksource_timebase.mult, clocksource_timebase.shift);
> +
> + init_decrementer_clockevent();
> }
>
> /* This function is only called on the boot processor */
> @@ -874,8 +932,7 @@ void __init time_init(void)
> /* Register the clocksource */
> clocksource_init();
>
> - /* Not exact, but the timer interrupt takes care of this */
> - set_dec(tb_ticks_per_jiffy);
> + set_dec(DECREMENTER_MAX);
> }
I don't think that set_dec() is needed any more. I get a very long
delay during "Calibrating delay loop..." with it there.
Looks like decrementer_set_next_event() already sets a reasonable
decementer value, it's called through the notify chain set off
from register_decrementer_clockevent() -> ... -> tick_notify() ->
tick_setup_periodic() -> clockevents_program_event().
-Olof
next prev parent reply other threads:[~2007-09-06 19:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-06 14:44 [RFC/PATCH 2/2] Generic clockevents and no-idle-HZ for PowerPC Paul Mackerras
2007-09-06 19:15 ` Olof Johansson [this message]
2007-09-06 20:03 ` Olof Johansson
2007-09-07 14:04 ` Johannes Berg
2007-09-07 19:16 ` Olof Johansson
2007-09-07 19:26 ` Johannes Berg
2007-09-07 20:59 ` Olof Johansson
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