Re: Old -rt patches

From: John Sigler
Date: Tue Aug 07 2007 - 04:53:00 EST


Paul E. McKenney wrote:

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 you be willing to post your app so people could try to reproduce
your bug?

Hello Paul,

I cannot provide the app "as is" (I fear the paranoid PHB would spontaneously combust). If time permits, I will try to make a small testcase to exhibit the problem.

Regards.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/