[ltt-dev] LTTng 0.47 and LTTV 0.11.4 saves event lost count in the subbuffer header

[Mathieu Desnoyers]

Hi,

I just released lttng 0.47 and lttv 0.11.4 which updates the trace
format to 2.2. There are two new fields in the subbuffer header :
lost_events and number of subbuffers corrupted so far for the specific
subbuffer. Note that those fields are 32 bits wide and may overflow.

LTTV prints warnings such as this when it encounters a trace with
corrupted subbuffers or lost events :

WARNING **: 170459 events lost so far in tracefile /tmp/trace/cpu_1 at block 76

If you encounter this, you will probably want to make your subbuffers
larger (see lttctl --help), keep the workload smaller or use the flight
recorder mode.

Before, users had to check for dmesg output after taking the trace to
see if there were events lost, which was somewhat inconvenient.

This new LTTng version also add new specialized trap/fault probes.

Mathieu

-- 
Mathieu Desnoyers
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