[ltt-dev] Crash recovery of traces and final TSC

Mathieu Desnoyers compudj at krystal.dyndns.org
Wed Jul 22 16:20:44 EDT 2009

* Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
> Mathieu Desnoyers wrote:
>> * Michel Dagenais (michel.dagenais at polymtl.ca) wrote:
>>>>> When the system crashes, the end timestamp is not written in the
>>>>> subbuffer header. Instead, the value 0 is written. This tends to make
>>>>> LTTV crash.
>>> Obviously LTTV should not "crash", whatever the input :-).
>>>>> - "repair" the trace a posteriori, writing in the header the timestamp
>>>>> of the last event found in the subbuffer?
>>>> Yep, seems like an appropriate solution.
>>>>> - change lttv not to not need the "end timestamp" header field?
>>>> Hrm, it needs it for quickly seeking to specific sub-buffers.
>>> People may expect the trace to be readonly, so relying on a posteriori
>>> fixing is kind of unexpected. You could have a special case for the last
>>> subbuffer, then not looking at the end time.
>> When we will create an index for variable-length sub-buffers, the fixup
>> could be computed and added to this index, if needed.
> Do we know when this is expected to be done?

It is not on my todo list at the moment. We'll have to assign some
resources to this task if you need it to be done.


>> I agree that the trace should stay read-only.
> Agreed.
>> Mathieu

Mathieu Desnoyers
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