Re: [RFD] Future tracing/instrumentation directions

[Thomas Gleixner <tglx@linutronix.de>]

On Thu, 20 May 2010, Frederic Weisbecker wrote:
> On Thu, May 20, 2010 at 11:31:31AM +0200, Ingo Molnar wrote:
> >  - [ While it's still a long way off, if this trend continues
> >      we eventually might even be able to get rid of the 
> >      /debug/tracing/ temporary debug API and get rid of 
> >      the ugly in-kernel pretty-printing bits. This is 
> >      good: it may make Andrew very happy for a change ;-)
> > 
> >      The main detail here to be careful of is that lots of
> >      people are fond of the simplicity of the 
> >      /debug/tracing/ debug UI, so when we replace it we 
> >      want to do it by keeping that simple workflow (or 
> >      best by making it even simpler). I have a few ideas 
> >      how to do this.
> 
> How? We can emulate the /debug/tracing result with something
> like perf trace, still that won't replace the immediate
> availability of the result of any trace, which makes it
> valuable for any simplest workflows.

I'm a bit torn about this. I really like the availability of the ascii
interface, but if we can come up with a very basic trace binary tool
which can be built for deep embedded w/o requiring the world and some
more libs to be available, then I might give up my resistance. Ideally
it should be done so it can be easily integrated into busybox.

I don't care whether I do

echo 1 >/debug/..../XXX/enable
cat /debug/tracing/trace

or

perfmini trace enable XXX
perfmini trace dump

as long as the tool is built in a way that it does not need updates
when we add trace points or other functionality to the kernel.

Thanks,

	tglx