Re: Profiling Kernel function blocks

[Domenico Di Leo <domenico dot dileo at unina dot it>]

I tried with systemtap 1.8, I can't change Kernel version.
and now I get the error message
Unknown symbol system_lookup_name during Pass 4.
The kernel is configured with CONFIG_KALLSUYMS_ALL=y.

On 8/2/2012 5:07 PM, Mark Wielaard wrote:
> On Thu, 2012-08-02 at 16:17 +0200, Domenico Di Leo wrote:
> > I was wondering if anybody has experienced a
> > hang of the entire OS when profiling
> > the functions of the kernel module.
> > In other words, when I run the following script
> > probe kernel.function("*@kernel/*.c").return{
> >       printf("%s  %s", threadindent(-1),probefunc());
> > }
> > the entire OS gets stuck.
> > I also tried with
> > probe kernel.function("*@kernel/*sched.c").return{
> >       printf("%s  %s", threadindent(-1),probefunc());
> > }
> > and after some printing the OS gets stuck again.
> This sounds like:
> Bug 2725 - function("*") probes sometimes crash&  burn
> http://sourceware.org/bugzilla/show_bug.cgi?id=2725
>
> > I'm using systemtap v1.4 and kernel 2.6.24 on Gentoo.
> Those are pretty old. You might want to try systemtap 1.8.
>
> Cheers,
>
> Mark


--
Domenico Di Leo, PhD student, Università degli Studi di Napoli Federico II
Ph:     +39 081 676770
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Web: http://wpage.unina.it/domenico.dileo (WP)