some questions about systemtap

[Arnaldo Carvalho de Melo]

Em Tue, Nov 25, 2008 at 04:20:39PM +0800, Peter Teoh escreveu:
> kernel path tracing is what systemtap is good at, for for TCP -
> evolution of stack trace indicate something of the kernel path
> traversed:

<SNIP>
 
> but for time measurement...u need another tool, possibly some network
> benchmarking tool.
> 
> 2008/11/25 zshan <zshan@cse.buaa.edu.cn>:
> >   Hello,
> >
> >   I and my mentor Mr hao （cc-ed in the mail ）want to research on is the
> > network I/O, which including dececting the network I/O path and the time
> > each process takes durning one network I/O request .
> >
> >   We wonder whether it is feasible ?
> >
> >   Any ideas ?

Something like this? For the TCP receive path as seen from functions
that have pointers to struct sock instances:

http://oops.ghostprotocols.net:81/acme/dwarves/callgraphs/sock/0xf61bf500/

More on
http://oops.ghostprotocols.net:81/acme/dwarves/callgraphs/

For dccp, that shares a lot of infrastructure with TCP:

http://oops.ghostprotocols.net:81/ostra/dccp/tx/
http://oops.ghostprotocols.net:81/ostra/dccp/rx/

It generates a systemtap script to insert the hooks at function
entry/exit and uses some postprocessing tools to generate the HTML + CSS
callgraphs, read about it at:

http://git.kernel.org/?p=linux/kernel/git/acme/pahole.git;a=blob_plain;f=README.ctracer

- Arnaldo