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To: Sebastian Huber <sebastian.huber@embedded-brains.de>
cc: freebsd-hackers@freebsd.org
Subject: Re: Problem with timecounters and memory model
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From: "Poul-Henning Kamp" <phk@freebsd.org>
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Date: Fri, 29 May 2015 21:38:47 +0000
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--------
In message <1056382604.51315.1432925656612.JavaMail.zimbra@embedded-brains=
.de>,
 Sebastian Huber writes:

>> If you only have one timehand, I can't see how it can work without
>> locks ?
>
>In RTEMS we have two build time configurations: uni-processor and SMP.

That makes sense.

Please note that the default value of 10 timehands was a totally random
number I pulled out of thin air.

The number should be chosen on how long time a thread can expect
to be preempted in kernel-mode, and since I suspect RTEMS to give
quite different guarantees than FreeBSD/UNIX, you may want to
think about that.

-- =

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    =

Never attribute to malice what can adequately be explained by incompetence=
.