Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCUissue?

From: Luotao Fu
Date: Wed Jul 09 2008 - 10:52:35 EST


Hi Wolfgang,
On Wed, Jul 09, 2008 at 03:15:01PM +0200, Wolfgang Grandegger wrote:
> Hi Fu (without n)
>
....
> OK, in the past you have been able to reproduce the high latencies with
> 2.6.24-rt1 and CONFIG_RCU_TRACE disabled, IIRC. Did you use a different
> toolchain at that time?
>

Nope. As mentioned above, trace_mark() does some "real" works (what ever it is.),
while the new mechahnismen use flags to remember the state of preemption. Maybe
something here got optimized away? I take for grant, that you use gcc in your
toolchain. Which version do you have?

cheers
Fu
--
Dipl.-Ing. Luotao Fu | Phone: +49-5121-206917-3
Pengutronix - Linux Solutions for Science and Industry
Entwicklungszentrum Nord http://www.pengutronix.de

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