[lttng-dev] [CTF] Dynamic enumerations and state system

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Mon Jan 16 21:16:53 EST 2012

Hi Alexandre,

Recently, I brought forward ideas about adding a new type, "dynamic
enumeration" to CTF. However, now that I come to think of it, these
dynamic enumerations would duplicate something that should probably be
done within the state system. Some information about the kind of
use-case it covers:

A "dynamic enumeration" could contain the mapping between IRQ handler
name and IRQ number. This listing is dynamically updated while the trace
is being recorded.

Adding a dynamic enumeration to CTF would only allow listing "global"
enumerations that are scoped across the entire OS. However, as soon as
we'd like to use them for, say, per process enumerations (hypothetical
example: listing mappings between signal number and the associated
handler), we cannot use a type as declared within CTF, because it has no
knowledge of the "per process" scoping in anyway: this is the state
system's job.

So my thoughts about this would be to possibly add a dynamic enumeration
type to the state system, in addition to the value, stack and possibly
other types it currently supports.

Thoughts ?



Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.

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