$ sudo -H lttng create sss
Session sss created.
Traces will be written in /root/lttng-traces/sss-20130625-103225
$ sudo -H lttng enable-channel u0 -u --buffers-uid
UST channel u0 enabled for session sss
$ sudo -H lttng enable-channel k0 -k
Kernel channel k0 enabled for session sss
$ sudo -H lttng start
Tracing started for session sss
$ sudo -H lttng stop
Waiting for data availability
Tracing stopped for session sss
$ sudo -H lttng enable-channel u4 -u --buffers-uid
UST channel u4 enabled for session sss
$ sudo -H lttng start
Tracing started for session sss
$ sudo -H lttng enable-channel u6 -u --buffers-uid --subbuf-size 4096
UST channel u6 enabled for session sss
$ sudo -H lttng stop
At which point LTTng hangs and must be killed manually. Once the session daemon is killed, the "Waiting for data availability" message appears, followed by an awful lot of periods.
commit d83004aa718065e5221d8ef4b99e4302b70b3df9
Author: Julien Desfossez <jdesfossez@efficios.com>
Date: Thu Jun 6 16:38:48 2013 -0400
Metadata cache and multiple metadata channels
Implement a cache for the kernel metadata and a list of metadata
channels.
When new metadata is appended, all metadata channels are awakened so
they can return from poll and get the newly added metadata
This allows to request the metadata multiple times by creating multiple
metadata channels (useful for snapshots).
With this new feature, the poll and get_subbuf ring buffer operations
are now overridden by lttng-abi for the metadata channels, to check the
cache before doing these operations.
Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>