[lttng-dev] lttng-ust works

Thibault, Daniel Daniel.Thibault at drdc-rddc.gc.ca
Tue Jan 14 15:10:33 EST 2014


> Trail 2:
> ========
> [...]
> lttng@/ # lttng -g lttng create as
> Session as created.
> Traces will be written in /home/lttng/lttng-traces/as-20131224-123811
> lttng@/ # lttng -g lttng enable-event -k -u -a
> All kernel events are enabled in channel channel0

   This is the culprit.  "lttng enable-event -k -u -a" will *only* enable the kernel events (the -k switch pre-empts the -u switch).  To enable kernel and user-space events, you must do two separate enable-event commands:

lttng@/ # lttng enable-event -k -a
lttng@/ # lttng enable-event -u -a

> Trail 3:
> ========
> [...]
> lttng@/ # lttng -g lttng create appses
> Session appses created.
> Traces will be written in /home/lttng/lttng-traces/appses-20131224-124354
> lttng@/ # lttng -g lttng enable-event -u -a
> All UST events are enabled in channel channel0
> lttng@/ # lttng -g lttng start
> Tracing started for session appses
> [...]
> The userspace trace files are generated
> No kernel traces are generated

   No kernel trace is generated because you did not enable any kernel events.

Daniel U. Thibault
Protection des systèmes et contremesures (PSC) | Systems Protection & Countermeasures (SPC)
Cyber sécurité pour les missions essentielles (CME) | Mission Critical Cyber Security (MCCS)
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