.TH "LTTNG" "1" "December 3rd, 2012" "" ""
.SH "NAME"
-lttng \(em LTTng 2.1.x tracer control command line tool
+lttng \(em LTTng 2.x tracer control command line tool
.SH "SYNOPSIS"
If no \fB\-o, \-\-output\fP is specified, the traces will be written in
$HOME/lttng-traces.
+
+The $HOME environment variable can be overridden by defining the environment
+variable LTTNG_HOME. This is useful when the user running the commands has
+a non-writeable home directory.
.fi
.B OPTIONS:
\-\-overwrite
Flight recorder mode : overwrites events when subbuffers are full
\-\-subbuf-size SIZE
- Subbuffer size in bytes {+k,+M,+G} (default: 4096, kernel default: 262144)
- Needs to be a power of 2 for both tracers
+ Subbuffer size in bytes {+k,+M,+G}
+ (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
+ Rounded up to the next power of 2.
\-\-num-subbuf NUM
- Number of subbuffers (default: 4)
- Needs to be a power of 2 for both tracers
+ Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4, metadata: 2)
+ Rounded up to the next power of 2.
\-\-switch-timer USEC
- Switch subbuffer timer interval in µsec (default: 0)
+ Switch subbuffer timer interval in µsec.
+ (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
\-\-read-timer USEC
- Read timer interval in µsec (UST default: 0, kernel default: 200000)
+ Read timer interval in µsec.
+ (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
\-\-output TYPE
Channel output type. Possible values: mmap, splice
+ (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
\-\-buffers-uid
Use per UID buffer (\-u only). Buffers are shared between applications
that have the same UID.
Use shared buffer for the whole system (\-k only)
\-C, \-\-tracefile-size SIZE
Maximum size of each tracefile within a stream (in bytes).
+ 0 means unlimited. (default: 0)
\-W, \-\-tracefile-count COUNT
Used in conjunction with \-C option, this will limit the number
- of files created to the specified count.
+ of files created to the specified count. 0 means unlimited. (default: 0)
.B EXAMPLES: