[lttng-dev] Answer to lttng perf counter question

[lttng-dev] Answer to lttng perf counter question

[Mathieu Desnoyers]

Hi,

Here is an answer to a question that was asked on #lttng today. Unfortunately,
the user left before we could answer.

10:13 < bonthink> Hi! Could someone help me? I am having problems after adding one specific perf counter perf:thread:stalled-cycles-frontend. If I do so, I 
                  am unable to view the traces afterwards. However other perf counters work fine. lttng 2.5.0
10:15 < bonthink> If using the hello example from the lttng doc it looks like this:
10:15 < bonthink> lttng view Trace directory: /home/user/lttng-traces/auto-20150602-160131  [error] Cannot open any trace for reading.  [error] opening 
                  trace "/home/aburov/lttng-traces/auto-20150602-160131" for reading.  [error] none of the specified trace paths could be opened.
10:16 < bonthink> and with some other perf counter
10:16 < bonthink> lttng view Trace directory: /home/aburov/lttng-traces/auto-20150602-160224  [16:03:14.431724221] (+?.?????????) krypton.tbricks.com 
                  hello_world:my_first_tracepoint: { cpu_id = 1 }, { perf_thread_cycles = 281474976715686 }, { my_string_field = "hi there!", 
                  my_integer_field = 23 } [16:03:14.432296656] (+0.000572435) krypton.tbricks.com hello_world:my_first_tracepoint: { cpu_id = 1 }, { 
                  perf_thread_cycles = 281474976722947 }, { my_s

Answer:

15:15 < Compudj> for bonthink (who is now gone): need to upgrade lttng version, looks like an already fixed issue about 64-bit contexts

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com