[lttng-dev] Lttng add-context perf commands gives me error

[Hani Nemati]

Hi, 
I am trying to count last level cache misses by using lttng add-context command. I use add-context to add perf:cpu:LLC-load-misses to my channel but I see an error. There is no error for other perf events. Just two perf events including perf:cpu:LLC-load-misses and  perf:cpu:LLC-store-misses give me the following error:
Error: perf:cpu:LLC-load-misses: Add kernel context failed
Warning: Some command(s) went wrong

Here is result of "uname -a" on my computer: 
Linux nemati 3.16.0-51-generic #69~14.04.1-Ubuntu SMP Wed Oct 7 15:32:41 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux 


Here is the command that I used: 
#lttng enable-channel -k test
#Kernel channel test enabled for session hh
#lttng add-context -k -t perf:cpu:LLC-load-misses -c test
Error: perf:cpu:LLC-load-misses: Add kernel context failed
Warning: Some command(s) went wrong


I also tried it on other machines.  <<<<<<<    /-/ /\ /\/ / /\/ E /\/\ /\ T /    >>>>>>>>
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