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Re: Tickless/dyntick kernel, highres timer and general time crapectomy

To: Franck Bui-Huu <vagabon.xyz@gmail.com>
Subject: Re: Tickless/dyntick kernel, highres timer and general time crapectomy
From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Date: Thu, 07 Jun 2007 18:49:59 +0400
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
In-reply-to: <cda58cb80706070744v21e1bbf3sa28990b4477a8844@mail.gmail.com>
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Hello.

Franck Bui-Huu wrote:

[ weird, Gmail thought you were a spamer... ]

   Well, I guess I should thank my ISP which indeed hosts many spammers. :-)

Sergei Shtylyov wrote:

   No, it doesn't. Even on dyntick kernels, interrupts do happen several
times a second. Dynticks have nothing to do with disabling timer
interrupts...


That's true however if your system has 2 clock devices. One is the r4k-hpt
and the other one soemthing else with a higher rating. If you don't stop
r4k-hpt interrupts, how does it work ?

The unwanted events just gets ignored by higher-level code, IIRC... Classic PowerPC CPUs have the same problem (even worse, actually) -- one can't disable the decrementer interrupt at all.

WBR, Sergei

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