Re: git: Bring in a simple event tracing library and POC utility

[Aggelos Economopoulos <aoiko@xxxxxxxxxxxxxx>]

Aggelos Economopoulos wrote:
> commit e7c0dbbaa9d5a2de52e8882628668615903e9132
> Author: Aggelos Economopoulos <aoiko@cc.ece.ntua.gr>
> Date:   Mon Feb 8 19:43:33 2010 +0200
> 
>     Bring in a simple event tracing library and POC utility

Please note that the code needs some serious cleanups, but I'm pushing
it in now because I'm sick of having to resolve merge conflicts again
and again.

I plan to change the libevtr API a bit; I'll write a manpage as soon as
it's reasonably stabilized. For now, evtranalyze(1) is your guide if you
want to know how to use the library.

The way to play with it is by doing ktrdump -d -o outfile.evtr -a and
then using evtranalyze -f outfile.evtr [command] (see the manpage). If
you try to display the svg output keep in mind that all of the
free/libre svg viewers out there will crash and or display garbage when
faced with such a huge file. Inkscape can handle it, but you need lots
of RAM (at least 1GB). You can use the -i option to generate a smaller
file. If you have KTR_CTXSW enabled, you should get the thread comm
field with each event (for newly created threads)

There's many things we could do with this infrastructure in place, maybe
I should put together a mail outlining possible future directions.

Comments (and patches...) welcome.

Aggelos