X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=doc%2Fman%2Flttng-enable-channel.1.txt;h=c4781c0f1953bfaad67382a9f948a686cd09fe9c;hb=55d7bb027104ac0afd80be872e0ff7ebb832216e;hp=bec0906428c5bfba6e9f91ab3e8f783cd96b472e;hpb=db0f7697361017ef0d00b2faf322b131b138fca5;p=lttng-tools.git diff --git a/doc/man/lttng-enable-channel.1.txt b/doc/man/lttng-enable-channel.1.txt index bec090642..c4781c0f1 100644 --- a/doc/man/lttng-enable-channel.1.txt +++ b/doc/man/lttng-enable-channel.1.txt @@ -16,6 +16,7 @@ Create a Linux kernel channel: [option:--overwrite] [option:--output=(`mmap` | `splice`)] [option:--subbuf-size='SIZE'] [option:--num-subbuf='COUNT'] [option:--switch-timer='PERIODUS'] [option:--read-timer='PERIODUS'] + [option:--monitor-timer='PERIODUS'] [option:--tracefile-size='SIZE'] [option:--tracefile-count='COUNT'] [option:--session='SESSION'] 'CHANNEL' @@ -26,7 +27,7 @@ Create a user space channel: [option:--overwrite] [option:--buffers-pid] [option:--subbuf-size='SIZE'] [option:--num-subbuf='COUNT'] [option:--switch-timer='PERIODUS'] [option:--read-timer='PERIODUS'] - [option:--blocking-timeout='TIMEOUTUS'] + [option:--monitor-timer='PERIODUS'] [option:--blocking-timeout='TIMEOUTUS'] [option:--tracefile-size='SIZE'] [option:--tracefile-count='COUNT'] [option:--session='SESSION'] 'CHANNEL' @@ -148,8 +149,8 @@ parameter is pointless: using two sub-buffers and setting their size according to the requirements of the context is fine. -Switch and read timers -~~~~~~~~~~~~~~~~~~~~~~ +Switch timer +~~~~~~~~~~~~ When a channel's switch timer fires, a sub-buffer switch happens. This timer may be used to ensure that event data is consumed and committed to trace files periodically in case of a low event throughput. @@ -157,11 +158,36 @@ to trace files periodically in case of a low event throughput. It's also convenient when big sub-buffers are used to cope with sporadic high event throughput, even if the throughput is normally lower. -By default, a notification mechanism is used to signal a full sub-buffer -so that it can be consumed. When such notifications must be avoided, -for example in real-time applications, the channel's read timer can be -used instead. When the read timer fires, sub-buffers are checked for -consumption when they are full. +Use the option:--switch-timer option to control the switch timer's +period of the channel to create. + + +Read timer +~~~~~~~~~~ +By default, an internal notification mechanism is used to signal a full +sub-buffer so that it can be consumed. When such notifications must be +avoided, for example in real-time applications, the channel's read timer +can be used instead. When the read timer fires, sub-buffers are checked +for consumption when they are full. + +Use the option:--read-timer option to control the read timer's period of +the channel to create. + + +Monitor timer +~~~~~~~~~~~~~ +When a channel's monitor timer fires, its registered trigger conditions +are evaluated using the current values of its properties (for example, +the current usage of its sub-buffers). When a trigger condition is true, +LTTng executes its associated action. The only type of action currently +supported is to notify one or more user applications. + +See the installed $$C/C++$$ headers in `lttng/action`, +`lttng/condition`, `lttng/notification`, and `lttng/trigger` to learn +more about application notifications and triggers. + +Use the option:--monitor-timer option to control the monitor timer's +period of the channel to create. Buffering scheme @@ -260,6 +286,19 @@ Default values: * option:--kernel option: {default_kernel_channel_subbuf_num} * `metadata` channel: {default_metadata_subbuf_num} +option:--output='TYPE':: + Set channel's output type to 'TYPE'. ++ +Available types: `mmap` (always available) and `splice` (only available +with the option:--kernel option). ++ +Default values: ++ +* option:--userspace and option:--buffers-uid options: `mmap` +* option:--userspace and option:--buffers-pid options: `mmap` +* option:--kernel option: `splice` +* `metadata` channel: `mmap` + option:--subbuf-size='SIZE':: Set the individual size of sub-buffers to 'SIZE' bytes. The `k` (kiB), `M` (MiB), and `G` (GiB) suffixes are supported. @@ -278,18 +317,6 @@ Default values: * option:--kernel option: {default_kernel_channel_subbuf_size} * `metadata` channel: {default_metadata_subbuf_size} -option:--output='TYPE':: - Set channel's output type to 'TYPE'. -+ -Available types: `mmap` (always available) and `splice` (only available -with the option:--kernel option). -+ -Default values: -+ -* option:--userspace and option:--buffers-uid options: `mmap` -* option:--userspace and option:--buffers-pid options: `mmap` -* option:--kernel option: `splice` -* `metadata` channel: `mmap` Buffering scheme ~~~~~~~~~~~~~~~~ @@ -333,6 +360,18 @@ discarded events as of CTF 1.8. Timers ~~~~~~ +option:--monitor-timer:: + Set the channel's monitor timer's period to 'PERIODUS' µs. 0 means a + disabled monitor timer. ++ +Default values: ++ +* option:--userspace and option:--buffers-uid options: + {default_ust_uid_channel_monitor_timer} +* option:--userspace and option:--buffers-pid options: + {default_ust_pid_channel_monitor_timer} +* option:--kernel option: {default_kernel_channel_monitor_timer} + option:--read-timer:: Set the channel's read timer's period to 'PERIODUS' µs. 0 means a disabled read timer.