[lttng-dev] missing kernel tracing modules

[Gerlando Falauto]

Hi,

I'm currently trying to use lttng-ust and I don't particularly care 
about kernel tracing, so I'm not even compiling the modules.

So as soon as I create a session I get the following:

root at kmeter1:~# lttng create
Spawning a session daemon
Warning: No tracing group detected
FATAL: Module lttng-tracer not found.
Error: Unable to load module lttng-tracer
FATAL: Module lttng-lib-ring-buffer not found.
Error: Unable to load module lttng-lib-ring-buffer
FATAL: Module lttng-ring-buffer-client-discard not found.
Error: Unable to load module lttng-ring-buffer-client-discard
FATAL: Module lttng-ring-buffer-client-overwrite not found.
Error: Unable to load module lttng-ring-buffer-client-overwrite
FATAL: Module lttng-ring-buffer-metadata-client not found.
Error: Unable to load module lttng-ring-buffer-metadata-client
FATAL: Module lttng-ring-buffer-client-mmap-discard not found.
Error: Unable to load module lttng-ring-buffer-client-mmap-discard
FATAL: Module lttng-ring-buffer-client-mmap-overwrite not found.
Error: Unable to load module lttng-ring-buffer-client-mmap-overwrite
FATAL: Module lttng-ring-buffer-metadata-mmap-client not found.
Error: Unable to load module lttng-ring-buffer-metadata-mmap-client
Error: Unable to remove module lttng-ring-buffer-metadata-mmap-client
Error: Unable to remove module lttng-ring-buffer-client-mmap-overwrite
Error: Unable to remove module lttng-ring-buffer-client-mmap-discard
Error: Unable to remove module lttng-ring-buffer-metadata-client
Error: Unable to remove module lttng-ring-buffer-client-overwrite
Error: Unable to remove module lttng-ring-buffer-client-discard
Error: Unable to remove module lttng-lib-ring-buffer
Error: Unable to remove module lttng-tracer
Warning: No kernel tracer available
Session auto-19700101-000339 created.
Traces will be written in /root/lttng-traces/auto-19700101-000339

As a workaround to get rid of these messages I could manually spawn 
lttng-sessiond with "--no-kernel".
Would it make sense to add such an option to the "lttng" wrapper command 
line, too?
So it could be passed over to lttng-sessiond, should you be aware that 
kernel tracing is not possibile to begin with (and you're not interested 
in it anyway).
What do you think?

Thank you,
Gerlando