\-\-overwrite
Flight recorder mode : overwrites events when subbuffers are full
\-\-subbuf-size SIZE
- Subbuffer size in bytes (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 (default: 200)
+ 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 per PID buffer (\-u only). Each application has its own buffers.
\-\-buffers-global
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. 0 means unlimited. (default: 0)
+
+.B EXAMPLES:
+
+$ lttng enable-channel -C 4096 -W 32 chan1
+For each stream, the maximum size of a trace file will be 4096 bytes divided
+over a \fBmaximum\fP of 32 different files. The file count is appended after
+the stream number as seen in the following example. The last trace file is
+smaller than 4096 since it was not completely filled.
+
+ ~/lttng-traces/[...]/chan1_0_0 (4096)
+ ~/lttng-traces/[...]/chan1_0_1 (4096)
+ ~/lttng-traces/[...]/chan1_0_2 (3245)
+ ~/lttng-traces/[...]/chan1_1_0 (4096)
+ ...
+
+$ lttng enable-channel -C 4096
+This will create trace files of 4096 bytes and will create new ones as long as
+there is data available.
.fi
.IP