This is the mail archive of the systemtap@sourceware.org mailing list for the systemtap project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Cross instrumentation with user space tracing enabled


Hi,
I am exploring the possibility of using Systemtap for our product.

My requirements are :
- Use Systemtap for user space and kernel space tracing added by developers.
- This means I am ok if i don't get in-build kernel probes
(debuginfo), but I must get traces/markers added in our user and
kernel code.

My setup is one of the most complex use case for systemtap :)
- Cross Instrumentation with user space trace support required.
- Host : Running CentOS 5.4 with?2.6.18-164.el5 i686
- Target : Self compiled Kernel?2.6.32.10 i686, image size max 512 mb.

My queries are as follows :
1)?I was able to run normal kernel scripts successfully on target, but
user space script is having issue.. it gives me error "Unknown symbol
in module". Searching on mailing list, found that it's due to uprobes.
Since I don't have compile env on target. ?need to compile uprobes
module for target on host. How do I do that ? I couldn't find option
to give target kernel version option for uprobe's make file.

2) Is it possible to use for 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 ?
As of now, I am working the long way of keeping debuginfo for target
on Host box itself, I can't afford debuginfo on target as it goes
beyond max image size.

3) This is with performance related. Pardon my kernel knowledge. How
the dynamic filtering of traces actually works ? E.g. If I have 10000+
markers in 5 diff user apps, but enables or uses only one app markers
in my systemtap script, how much overhead those remaining markers in
other apps are going to add ?

Thanks and Regards,
hp


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]