[ltt-dev] General Questions

[Kevin Harms]

Mathieu,

  applying the 0.12 patch to 2.6.26 worked cleanly. I built the kernel but it seems like it didn't enable the correct options.

ts14:~ # ltt-armall
Connecting all markers
cat: /proc/ltt: No such file or directory

  Under Kernel Hacking, I think i found a LTT option that was checked when i did a make menuconfig. But i didn't see the extensive list of options detailed on the web. For the 2.6.26, what do i need to enable in the make menuconfig?

thanks,
kevin
  
----- Original Message -----
From: "Mathieu Desnoyers" <compudj at krystal.dyndns.org>
To: "Kevin Harms" <harms at alcf.anl.gov>
Cc: "Michel Dagenais" <michel.dagenais at polymtl.ca>, ltt-dev at lists.casi.polymtl.ca
Sent: Saturday, July 26, 2008 12:19:40 AM GMT -06:00 US/Canada Central
Subject: Re: [ltt-dev] General Questions

Can you try applying patch-2.6.26-0.12.tar.bz2 instead ? I may have
forgot to refresh a patch in 0.11 before doing the release.

Mathieu

* Kevin Harms (harms at mcs.anl.gov) wrote:
> 
>   I'm having trouble building a lttng enabled kernel. I'm using the following command to patch a 2.6.26 kernel.
> 
> for f in $(cat ../lttng/patch-2.6.26-0.11/series | egrep -v "^#"); do patch --dry-run -p1 < ../lttng/patch-2.6.26-0.11/${f}; done
> 
>   Some of the patches apply correctly, but I get a few of these:
> 
> patching file kernel/module.c
> Hunk #1 FAILED at 47.
> Hunk #2 succeeded at 1386 (offset -1 lines).
> Hunk #3 succeeded at 2162 (offset -17 lines).
> 1 out of 3 hunks FAILED -- saving rejects to file kernel/module.c.rej
> 
>   I'm using kernel 2.6.26.
> 
> thanks,
> kevin
> 
> ----- Original Message -----
> From: "Michel Dagenais" <michel.dagenais at polymtl.ca>
> To: "Kevin Harms" <harms at alcf.anl.gov>
> Cc: ltt-dev at lists.casi.polymtl.ca
> Sent: Tuesday, July 22, 2008 4:15:54 PM GMT -06:00 US/Canada Central
> Subject: Re: [ltt-dev] General Questions
> 
> 
> > I'm looking into an issue where fsync() is being called repeatedly by
> > an application but some of those fsync() calls stall sometimes. Would
> > LTT be useful for trying to see what is happening inside the kernel
> > that causes those fsync() calls to stall?
> 
> Yes, very much! Fsync is relatively infrequent and easy to search for in
> a trace. From there you need the detailed scheduling information to
> understand why it is blocking, which is exactly what LTT will give you.
> 
> 
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-- 
Mathieu Desnoyers
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