Re: [microblaze-uclinux] Linux Trace Toolkit and microblaze

[Alejandro Lucero <alucero@xxxxxxxxx>]

Hi John,

On Thursday 29 March 2007 01:53, John Williams wrote:
> Hi Alejandro,
>
> Alejandro Lucero wrote:
> > During the rtlinux port to microblaze, I have used an ad-hoc kernel trace
> > system. I want to use this experience and effort to obtain a compatible
> > LTT trace toolkit, so we can use the current graph tools from LTT and
> > LTTng projects.
> >
> > Any idea or commentary will be appreciated.
>
> Sounds like it would be very useful.  Why not use LTTng as it is, rather
> than re-implementing a compatible trace toolkit?

I have just done a preliminary study, but I think the key point is to use the 
same event/trace format used in LTT or LTTng (is it not the same?). Then we 
can use the visual tools from these projects.

How these event/trace points are implemented? I don't know how this is done 
usually, but I have the interrupts, system calls and context switches trace 
code in assembler (entry.S). Perhaps, I can use the usual implementations for 
other points as process creation/destruction, signals and dynamic memory 
requests.

> A quick glance at the latest patch sets shows some arch-specific work
> will be required, but given your time spent deep in the guts working on
> RTLinux I'm sure you're up to the task!

The latest patch for 2.4 or 2.6? 
I must say I'm a bit misinformed about which is the current state of 2.6 port, 
who is the maintainer, ...

> A couple of observations
>   * LTTng (new generation) targets recent 2.6 kernels (2.6.12 onwards)
>   * original LTT development ended at 2.4.16, and 2.5.something
>   * it looks like LTT requires modules - 2.6 for microblaze doesn't have
> loadable module support yet (oh joy, ELF relocs :)
>   * look around to see if anyone is already running LTT on an nommu
> architecture.  in particular the runtime logging daemon would be a good
> candidate for nommu pain (forking, mmapping files and so on).

> I'd encourage you to use LTTng (and thus 2.6) if you were going to do
> this, but that's entirely up to you.
>
> Cheers,
>
> John
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