Kernel instrumentation for dummies

[oldpondfrog]

I am not a kernel hacker. But even for somebody like me there is System Tap which can help you find really cool stuff like this in a matter of minutes!!
No writing modules/creating probes/recompiling kernel!!  Works almost out of the box with FC4 and above.
Saved me a ton of work for my research...bless them!!

Comments

[karthiks]

awesome !

[jithamithra]

I need more info on this.
(Especially the exercise 4)

[jithamithra]

it seems to me there are tons of probe points (basically and address in the kernel's code you want to tap into or a function symbol like gdb used)

so if you want say pid of the process running on a cpu (in an SMP) look at the scheduler code inside the kernel which will do the context switch , follow the process data structres to get pid and simply start logging.

but my dear fellow there is still no escape from knowing WHERE in the kernel you want to probe and WHICH data structures will give you the info you want!
look at some examples on the webpage to understand this better.

[karthiks]

this looks like the DTrace of the linux world