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Re: Cross instrumentation with user space tracing enabled


Okie.. First issue solved by doing manual insmod of uprobes before
running staprun on target.

On Mon, Dec 6, 2010 at 12:50 PM, h patel <hpatel05@gmail.com> wrote:
> 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
>


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