On Wed, Oct 25, 2006 at 02:34:28AM +0900, Atsushi Nemoto wrote:
> Date: Wed, 25 Oct 2006 02:34:28 +0900 (JST)
> To: ralf@linux-mips.org
> Cc: creideiki+linux-mips@ferretporn.se, linux-mips@linux-mips.org
> Subject: Re: Extreme system overhead on large IP27
> From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
> Content-Type: Text/Plain; charset=us-ascii
>
> On Tue, 24 Oct 2006 16:50:45 +0100, Ralf Baechle <ralf@linux-mips.org> wrote:
> > > 2. Timekeeping is broken. The clock in /proc/driver/rtc seems correct, but
> > > the system clock advances at about 1/16 of real time.
> >
> > This one was caused by changeset ebca9aafa9bd5086d9f310205a8e30e225c5a5a6
> > which apparently wasn't quite ripe. You can work around it by
> > revoking this changeset for now. The time damage affects other systems
> > as well ...
>
> Now I'm looking my patch again but still can not find any problem...
>
> One question:
>
> > # zcat /proc/config.gz | grep HZ | grep -v ^#
> > CONFIG_HZ_250=y
> > CONFIG_SYS_SUPPORTS_ARBIT_HZ=y
> > CONFIG_HZ=250
>
> IP27 really supports HZ=250 ?
Arbitrary frequency actually. The timer used is the HUB timer which is
running at 800ns afair. It's like 53 bits or so. There is also a compare
register so it's somewhat similar to the cop0 counter / compare timer.
Ralf
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