Xen devel - Jul 2006 - [Xen-tools] Dprobe and Systemtap for Xen Tracing and Debugging.

Hi folks

In linux kernel development, there is a debug tool called dprobe ,which can
be used to dynamic insert the probes into the function of kernel source code
and find what''s goning on.There is also a tool called systemtap which
is
based on dprobe and kernel debug info.
Using the kprobes infrastructure, SystemTap is being developed to
dynamically instrument the kernel and user applications.
In this way,we can diagnose complex problems without multiple rebuilds and
reboots.

Can xen use this kind of tools for xen tracing and debugging ? As we know
,the capability of performace tracing tools (xenoprof)for xen is limited
comparing with dprobe and systemtap.Dose anyone have any good idea about
this ?

My idea is we cab make use of dprobe and systemtap to build a more powerful
and covenient tool for xen performance tracing and debugging.

----
Regards
Ding Rui(Rickey)


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Sounds like a great idea to me!  I doubt that the hypervisor itself is
already ready for kprobes, but I hope that it''s not to hard to get
working ...

Peace,
Andrew

On Mon, 2006-07-31 at 21:00 +0800, rickey berkeley
wrote:
> Hi folks 
>  
> In linux kernel development, there is a debug tool called
> dprobe ,which can be used to dynamic insert the probes into the
> function of kernel source code and find what''s goning on.There is
also
> a tool called systemtap which is based on dprobe and kernel debug
> info.
> Using the kprobes infrastructure, SystemTap is being developed to
> dynamically instrument the kernel and user applications.
> In this way,we can diagnose complex problems without multiple rebuilds
> and reboots.
>  
> Can xen use this kind of tools for xen tracing and debugging ? As we
> know ,the capability of performace tracing tools (xenoprof)for xen is
> limited comparing with dprobe and systemtap.Dose anyone have any good
> idea about this ?
>  
> My idea is we cab make use of dprobe and systemtap to build a more
> powerful and covenient tool for xen performance tracing and
> debugging. 
> 
> ----
> Regards 
> Ding Rui(Rickey)
>  
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

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> Can xen use this kind of tools for xen tracing and debugging ? As we know
> ,the capability of performace tracing tools (xenoprof)for xen is limited
> comparing with dprobe and systemtap.Dose anyone have any good idea about
> this ?
IIRC Linux''s dynamic kernel probing relies on being able to load kernel
modules with custom probing code included.  There''s currently not
loadable
module support in Xen, so if we wanted to be able to do this, we''d have
to
find a way to add it.
> My idea is we cab make use of dprobe and systemtap to build a more powerful
> and covenient tool for xen performance tracing and debugging.
You could get quite a long way by inserting probes into all the guest kernels 
(and apps) and implementing some tools to tie all the results together - that 
could give you quite a bit of insight into what was going on.

You could probably also usefully gather other data from the Xen trace buffers 
(scheduling events, etc) to correlate with this data for the final analysis.  
This could be quite powerful without needing to insert code into Xen itself.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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>
>
> Thanks all for your advice.
> ----
> Regards
> Ding Rui(Rickey)

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