трассировка пространства пользователя LTTng (LTTng user space tracing)
Переменные окружения (Environment variables)
LTTNG_HOME
Alternative user's home directory. This variable is useful
when the user running the instrumented application has a
non-writable home directory.
Unix sockets used for the communication between liblttng-ust
and the LTTng session and consumer daemons (part of the
LTTng-tools project) are located in a specific directory
under $LTTNG_HOME (or $HOME if $LTTNG_HOME is not set).
LTTNG_UST_ALLOW_BLOCKING
If set, allow the application to retry event tracing when
there's no space left for the event record in the sub-buffer,
therefore effectively blocking the application until space is
made available or the configured timeout is reached.
To allow an application to block during tracing, you also
need to specify a blocking timeout when you create a channel
with the --blocking-timeout option of the
lttng-enable-channel(1) command.
This option can be useful in workloads generating very large
trace data throughput, where blocking the application is an
acceptable trade-off to prevent discarding event records.
Warning
Setting this environment variable may significantly
affect application timings.
LTTNG_UST_CLOCK_PLUGIN
Path to the shared object which acts as the clock override
plugin. An example of such a plugin can be found in the
LTTng-UST documentation under examples/clock-override
<https://github.com/lttng/lttng-
ust/tree/v2.10.6/doc/examples/clock-override>.
LTTNG_UST_DEBUG
If set, enable liblttng-ust's debug and error output.
LTTNG_UST_GETCPU_PLUGIN
Path to the shared object which acts as the getcpu() override
plugin. An example of such a plugin can be found in the
LTTng-UST documentation under examples/getcpu-override
<https://github.com/lttng/lttng-
ust/tree/v2.10.6/doc/examples/getcpu-override>.
LTTNG_UST_REGISTER_TIMEOUT
Waiting time for the registration done session daemon command
before proceeding to execute the main program (milliseconds).
The value 0 means do not wait. The value -1 means wait
forever. Setting this environment variable to 0 is
recommended for applications with time constraints on the
process startup time.
Default: 3000.
LTTNG_UST_WITHOUT_BADDR_STATEDUMP
If set, prevents liblttng-ust from performing a base address
state dump (see the LTTng-UST state dump section above).
