Re: Is it possible to use Systemtap without debuginfo?

Re: Is it possible to use Systemtap without debuginfo?

[Frank Ch. Eigler]

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Hi -

deepak.venkatesh wrote:
>     - Use Systemtap for user space and kernel space tracing.
>     - This means I must get traces/markers added in our user and kernel
>       code.

Not quite: you only need tracepoints/markers added to the target code
if you cannot get hold of dwarf debuginfo.  Plus kernel & userspace
debuginfo are independent requirements.

>     My setup is :
>      ubuntu 10.10 with kernel 2.6.35-22-generic i686, which is not
> utrace enabled i.e., CONFIG_UTRACE is not available.
>  
>     My queries are as follows :
>    
>     1. Is it possible to use Systemtap without debuginfo ? e.g. Only
> with Kernel Markers support and User space traces enabled.  If yes, can
> you direct me to related help page ?

This is briefly described in the stap/stapprobes man pages.  The gist
of it is that the following probe point types do or do not require
debuginfo.  Your particular script's needs are determined by which
probe point types you use in it.

NO DWARF                          YES DWARF

kprobe.function(...)              kernel.statement(), module(...).function(...)
kernel.trace(...)
process(...).mark(...)            process(...).function(...) etc.
timer.*
perf.*
procfs.*
begin/end/

I'll add a more compact table like this to our man pages.

>     2. As I need utrace for user space tracing, how can I build a kernel
> that supports utrace and also provides debuginfo.?
>     3. I am not able to find debuginfo package for kernel
> 2.6.35-22-generic i686. Please provide information on kernels that is
> utrace enabled and also provide debuginfo.

Just yesterday we came across a ubuntu PPA whose maintainer has kindly
assembled just this:
<http://sourceware.org/ml/systemtap/2011-q1/msg00276.html>
You may wish to investigate and replicate this work so you're not
dependent on Mr. Peijnik.

Please be aware that the ubuntu kernel configuration is different
enough from the ones we usually test on that some new problems may be
seen.  We will endavour to fix those problems.

- FChE

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Re: Is it possible to use Systemtap without debuginfo?

[Frank Ch. Eigler]

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Hi -

On Thu, Feb 17, 2011 at 07:52:39PM +0530, deepak.venkatesh@wipro.com wrote:
> [...]
> The steps I followed for installing systemtap are:
> 
> 1. Downloaded and installed following packages:
> linux-image-2.6.35-26-generic_2.6.35-26.46~utrace0_i386.deb,
> linux-headers-2.6.35-26_2.6.35-26.46~utrace0_all.deb,
> linux-headers-2.6.35-26-generic_2.6.35-26.46~utrace0_i386.deb and
> linux-image-2.6.35-26-generic-dbgsym_2.6.35-26.46_i386.ddeb in the same
> order.  [...]

I think the missing step was rebooting into that new kernel.

- FChE

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Re: Is it possible to use Systemtap without debuginfo?

[Frank Ch. Eigler]

Hi -

> I was able to run the command "stap -ve 'probe begin { log("hello
> world") exit() }'". This was achieved by installing systemtap-1.4.

OK, good.  See if this also works:

stap -tve '
 probe kernel.function("sys_open") {}
 probe process("stap").function("main") {}
' -c 'stap -V'

> Previously it was failing for systemtap-0.2.2. Please help on this. 

Systemtap 0.2.2 was our very first release, almost six years ago, so
failures with that would not be surprising.  Perhaps you meant 1.2?
Anyway, stick to 1.4 if you can.

- FChE