How to monitor thread scheduling and the criticality of tasks?

Björn Döbel doebel at os.inf.tu-dresden.de
Wed Nov 5 14:04:08 CET 2014


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Hi,

> How can you monitor how threads are scheduled for execution in
> L4Re? The trace buffer does not seem to offer information about
> the criticality of tasks.

if you are purely interested in scheduling events, you might want to
look at the kernel trace buffer. Build Fiasco with 'extended JDB
logging' enabled. Then at runtime you can hit <Esc> to enter the
kernel debugger and then use 'o' to select which events to trace.
Press 'g' to continue and later hit <ESC> again to return to JDB. Then
press 'T' to view the trace buffer which will then contain scheduling
information.

What do you mean by 'information about the criticality'?

> The l4re-snapshot-2014092821, however, refers to a monitoring
> framework named "ferret" in  /obj/l4linux/ux/source/arch/l4/Kconfig
> but does not provide its source code. Is ferret publicly
> available?

Ferret is/was an event monitoring framework that allowed to collect
events at the kernel and user level and incorporate them into a single
event stream. It has not been updated for quite some time and is
therefore no longer part of the snapshot.

Maybe we can help you more if you describe your specific problem in
more detail?

Cheers,
Bjoern
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