Message-ID: <46B6E210.9090502@free.fr>
Date: Mon, 06 Aug 2007 10:55:44 +0200
From: John Sigler <linux.kernel@free.fr>
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To: linux-rt-users@vger.kernel.org
CC: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de
Subject: Re: Old -rt patches
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John Sigler wrote:

> I wrote a Linux app where I need high-resolution timers. I went all the 
> way and installed the -rt patch, which includes the -hrt patches, as far 
> as I understand.
> 
> Since I could not afford to change kernels with every new release, I 
> decided to track the 2.6.20 branch (arbitrarily).
> 
> At this point I'm using 2.6.20.7-rt8 (-rt8 was the last patch to the 
> 2.6.20 branch). (I see 2.6.20 is already up to .15)
> 
> I see a lot of patches going into the -rt patch, but development moved 
> on to 2.6.21, then 2.6.22, and now 2.6.23, following mainline.
> 
> I'm not a kernel hacker, so I don't claim to understand the patches, but 
> the comments sound like a few bugs are fixed here and there. I can't 
> tell whether these bugs also exist in previous kernels or only appeared 
> in newer kernels. Even if I knew, I probably wouldn't have the expertise 
> to back-port the patch.
> 
> I'm seeing weird behavior in my app, when it has been running 2-4 days. 
> The timers start to act out, and all hell breaks loose. Basically, I 
> have no idea what's going on...
> 
> My question is: is it possible that there is a bug in 2.6.20-rt8 that 
> has been fixed in subsequent -rt patches (there's a 2.6.21.6-rt21 and a 
> 2.6.22.1-rt9)? In other words, if I give 2.6.21.6-rt8 or 2.6.22.1-rt9 a 
> spin, is it possible that my weird behavior disappears?
> 
> I'm not saying that it's impossible for the bug to be in my app, but the 
> app is small enough that I'm fairly confident there's no problem there.

Would anyone care to comment?

Perhaps I could also test a different strategy, such as xenomai?
http://www.xenomai.org/

Regards.
-
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