[lttng-dev] Reading cache misses in Userspace?

[alexander.kampmann@gmx.de (Alexander Kampmann)]

hey,

I would like to find out which part of my application causes most cache 
misses. So I tried to add userspace events to my application. I hoped 
LTTng would give me some mean of determining between which tracepoints 
the most cache misses occur.

I started a session like that:

sudo lttng create session
sudo lttng enable-event -a -u
sudo lttng add-context -u -t perf:LLC-load-misses -t 
perf:LLC-store-misses -t perf:LLC-prefetch-misses

I get:

Error: perf:LLC-prefetch-misses: UST invalid context
Error: perf:LLC-store-misses: UST invalid context
Error: perf:LLC-load-misses: UST invalid context

Does this mean I can not add perf:LLC-* context to my userspace events? 
Is there any way to figure out which part of my application causes cache 
misses?

If I use

sudo lttng add-context -k -t perf:LLC-load-misses -t 
perf:LLC-store-misses -t perf:LLC-prefetch-misses

instead, I don't get an error, but the babeltrace output does not 
contain any cache miss counts as well.

I would appreciate any help,

Alex