LTTng » LTTng-tools

Using lttng 2.3.0

In the kernel domain, the loglevel and loglevel-only event options are ignored if the event type is --syscall, but an error is issued if it is --probe or --function. If the --all option is also used, the interface feedback gives the impression that lttng accepts loglevel filtering, but the session configuration actually ignores it. Thus:

$ lttng enable-event -k sched_switch --loglevel-only warn
Kernel loglevels are not supported
Error: Unsupported command

$ lttng enable-event -k myprobe --probe kvm_fpu+0x0 --loglevel-only warn
Kernel loglevels are not supported
Error: Unsupported command

$ lttng enable-event -k --all --syscall --loglevel-only warn
All kernel system calls are enabled in channel channel0
$ lttng list session
[…]
    Events:
      syscalls (type: syscall) [enabled]

$ lttng enable-event -k --all --loglevel-only warn
All kernel events are enabled in channel channel0 for loglevel warn
$ lttng list session
[…]
    Events:
[…]
      kvm_fpu (loglevel: TRACE_EMERG (0)) (type: tracepoint) [enabled]