[ltt-dev] Bug in LTTv statistics ?

[Mathieu Desnoyers]

* Copelnug (copelnug at gmail.com) wrote:
> There seems to be a bug in the LTTv statistics.
> 
> The problems is visible in the function "every_event" of the lttv/stats.c
> file. That function is called for each event and receive a
> "LttvTracefileStats" structure as parameter.
> 
> So if you check the value of the pointer to the "LttvTracefileStats"
> received, you can see it changing between 15 and 20 value depending of the
> trace loaded. This seems to be intended to me because each type of events is
> associated with one and only one "LttvTracefileStats" (but a structure can
> have many events type).
> 
> The bug seems to be a side effect : The structure passed to the function
> contain the current path to the "current_event_types_tree" that is used to
> increase the numbers of event for the event type. Or, this value is not
> conserved between two "LttvTracefileStats" which means that the change of
> process or state only affect one "LttvTracefileStats" and let the others to
> their value. That means that some types of event are never affected by a
> change of mode or process.
> 
> What this cause is :
> - Many event in process 0 and Unknown mode.
> - Difference between the total for a process of the event list in the
> textdump and the value for the process in the statistics of the same
> textdump.
> 
> Is it really a problem or am I misunderstanding something ?

Ack, I'm currently digging in the stats code to try to fix the problem.
Thanks for the precise bug report.

Mathieu

> 
> Note : I use LTTv version 0.12.31 with trace version 2.5 and 2.6.

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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com