X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=doc%2Fman%2Flttng-ust.3.txt;h=bf24967231b756d0d58fbec18e79b0fb329d148a;hb=2842c6c82f70ff2c5a996c063cc7d2ef2a06f289;hp=2fddbdc5e8a12ddc30d03f7242756282a793080d;hpb=4ddbd0b790be981d023f344a83e67a8746fa3688;p=lttng-ust.git diff --git a/doc/man/lttng-ust.3.txt b/doc/man/lttng-ust.3.txt index 2fddbdc5..bf249672 100644 --- a/doc/man/lttng-ust.3.txt +++ b/doc/man/lttng-ust.3.txt @@ -23,6 +23,12 @@ SYNOPSIS #define *TRACEPOINT_LOGLEVEL*('prov_name', 't_name', 'level') #define *ctf_array*('int_type', 'field_name', 'expr', 'count') #define *ctf_array_nowrite*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_hex*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_nowrite_hex*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_network*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_network_nowrite*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_network_hex*('int_type', 'field_name', 'expr', 'count') +#define *ctf_array_network_nowrite_hex*('int_type', 'field_name', 'expr', 'count') #define *ctf_array_text*(char, 'field_name', 'expr', 'count') #define *ctf_array_text_nowrite*(char, 'field_name', 'expr', 'count') #define *ctf_enum*('prov_name', 'enum_name', 'int_type', 'field_name', 'expr') @@ -38,8 +44,20 @@ SYNOPSIS #define *ctf_integer_network_hex*('int_type', 'field_name', 'expr') #define *ctf_integer_nowrite*('int_type', 'field_name', 'expr') #define *ctf_sequence*('int_type', 'field_name', 'expr', 'len_type', 'len_expr') -#define *ctf_sequence_nowrite*('int_type', 'field_name', 'expr', - 'len_type', 'len_expr') +#define *ctf_sequence_nowrite*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +#define *ctf_sequence_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +#define *ctf_sequence_nowrite_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +#define *ctf_sequence_network*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +#define *ctf_sequence_network_nowrite*('int_type', 'field_name', 'expr', + 'len_type', 'len_expr') +#define *ctf_sequence_network_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +#define *ctf_sequence_network_nowrite_hex*('int_type', 'field_name', 'expr', + 'len_type', 'len_expr') #define *ctf_sequence_text*(char, 'field_name', 'expr', 'len_type', 'len_expr') #define *ctf_sequence_text_nowrite*(char, 'field_name', 'expr', 'len_type', 'len_expr') @@ -250,11 +268,18 @@ Null-terminated string: *ctf_string*('field_name', 'expr') *ctf_string_nowrite*('field_name', 'expr') -Statically-sized array of integers: +Statically-sized array of integers (`_hex` versions displayed in +hexadecimal, `_network` versions in network byte order): [verse] *ctf_array*('int_type', 'field_name', 'expr', 'count') *ctf_array_nowrite*('int_type', 'field_name', 'expr', 'count') +*ctf_array_hex*('int_type', 'field_name', 'expr', 'count') +*ctf_array_nowrite_hex*('int_type', 'field_name', 'expr', 'count') +*ctf_array_network*('int_type', 'field_name', 'expr', 'count') +*ctf_array_network_nowrite*('int_type', 'field_name', 'expr', 'count') +*ctf_array_network_hex*('int_type', 'field_name', 'expr', 'count') +*ctf_array_network_nowrite_hex*('int_type', 'field_name', 'expr', 'count') Statically-sized array, printed as text; no need to be null-terminated: @@ -262,11 +287,22 @@ Statically-sized array, printed as text; no need to be null-terminated: *ctf_array_text*(char, 'field_name', 'expr', 'count') *ctf_array_text_nowrite*(char, 'field_name', 'expr', 'count') -Dynamically-sized array of integers: +Dynamically-sized array of integers (`_hex` versions displayed in +hexadecimal, `_network` versions in network byte order): [verse] *ctf_sequence*('int_type', 'field_name', 'expr', 'len_type', 'len_expr') *ctf_sequence_nowrite*('int_type', 'field_name', 'expr', 'len_type', 'len_expr') +*ctf_sequence_hex*('int_type', 'field_name', 'expr', 'len_type', 'len_expr') +*ctf_sequence_nowrite_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +*ctf_sequence_network*('int_type', 'field_name', 'expr', 'len_type', 'len_expr') +*ctf_sequence_network_nowrite*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +*ctf_sequence_network_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') +*ctf_sequence_network_nowrite_hex*('int_type', 'field_name', 'expr', 'len_type', + 'len_expr') Dynamically-sized array, displayed as text; no need to be null-terminated: @@ -753,11 +789,12 @@ Only available on IA-32 and x86-64 architectures. the process namespace. +[[state-dump]] LTTng-UST state dump ~~~~~~~~~~~~~~~~~~~~ If an application that uses `liblttng-ust` becomes part of a tracing session, information about its currently loaded shared objects, their -build IDs, and their debug link informations are emitted as events +build IDs, and their debug link information are emitted as events by the tracer. The following LTTng-UST state dump events exist and must be enabled @@ -775,19 +812,21 @@ This event has no fields. + This event has no fields. -`lttng_ust_statedump:soinfo`:: - Emitted when information about a currently loaded shared object is - found. +`lttng_ust_statedump:bin_info`:: + Emitted when information about a currently loaded executable or + shared object is found. + Fields: + [options="header"] -|============================================================== +|================================================================== | Field name | Description -| `baddr` | Base address of loaded library -| `memsz` | Size of loaded library in memory -| `sopath` | Path to loaded library file -|============================================================== +| `baddr` | Base address of loaded executable +| `memsz` | Size of loaded executable in memory +| `path` | Path to loaded executable file +| `is_pic` | Whether the executable is + position-independent code +|================================================================== `lttng_ust_statedump:build_id`:: Emitted when a build ID is found in a currently loaded shared @@ -832,7 +871,53 @@ This example shows all the features documented in the previous sections. The <> method is chosen here to link the application with the tracepoint provider. -Let's start with the tracepoint provider header file (`tp.h`): +You can compile the source files and link them together statically +like this: + +[role="term"] +------------------------------------- +cc -c -I. tp.c +cc -c app.c +cc -o app tp.o app.o -llttng-ust -ldl +------------------------------------- + +Using the man:lttng(1) tool, create an LTTng tracing session, enable +all the events of this tracepoint provider, and start tracing: + +[role="term"] +---------------------------------------------- +lttng create my-session +lttng enable-event --userspace 'my_provider:*' +lttng start +---------------------------------------------- + +You may also enable specific events: + +[role="term"] +---------------------------------------------------------- +lttng enable-event --userspace my_provider:big_event +lttng enable-event --userspace my_provider:event_instance2 +---------------------------------------------------------- + +Run the application: + +[role="term"] +-------------------- +./app some arguments +-------------------- + +Stop the current tracing session and inspect the recorded events: + +[role="term"] +---------- +lttng stop +lttng view +---------- + + +Tracepoint provider header file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +`tp.h`: ------------------------------------------------------------------------ #undef TRACEPOINT_PROVIDER @@ -953,7 +1038,10 @@ TRACEPOINT_EVENT_INSTANCE( #include ------------------------------------------------------------------------ -The tracepoint provider source file looks like this (`tp.c`): + +Tracepoint provider source file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +`tp.c`: ------------------------------------------------------------------------ #define TRACEPOINT_CREATE_PROBES @@ -962,7 +1050,10 @@ The tracepoint provider source file looks like this (`tp.c`): #include "tp.h" ------------------------------------------------------------------------ -The included `app.h`, where the application structure resides, is: + +Application header file +~~~~~~~~~~~~~~~~~~~~~~~ +`app.h`: ------------------------------------------------------------------------ #ifndef _APP_H @@ -977,7 +1068,10 @@ struct app_struct { #endif /* _APP_H */ ------------------------------------------------------------------------ -Finally, the application itself, `app.c`, using the defined tracepoints: + +Application source file +~~~~~~~~~~~~~~~~~~~~~~~ +`app.c`: ------------------------------------------------------------------------ #include @@ -1027,15 +1121,90 @@ int main(int argc, char* argv[]) } ------------------------------------------------------------------------ -Here are the steps to compile the source files and link them together -statically: -[role="term"] -------------------------------------- -cc -c -I. tp.c -cc -c app.c -cc -o app tp.o app.o -llttng-ust -ldl -------------------------------------- +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_BLOCKING_RETRY_TIMEOUT`:: + Maximum duration (milliseconds) to retry event tracing when + there's no space left for the event record in the sub-buffer. ++ +-- +`0` (default):: + Never block the application. + +Positive value:: + Block the application for the specified number of milliseconds. If + there's no space left after this duration, discard the event + record. + +Negative value:: + Block the application until there's space left for the event record. +-- ++ +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 to a non-zero value 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 + https://github.com/lttng/lttng-ust/tree/master/doc/examples/clock-override[`examples/clock-override`]. + +`LTTNG_UST_DEBUG`:: + Activates `liblttng-ust`'s debug and error output if set to `1`. + +`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 + https://github.com/lttng/lttng-ust/tree/master/doc/examples/getcpu-override[`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: {lttng_ust_register_timeout}. + +`LTTNG_UST_BLOCKING_RETRY_TIMEOUT`:: + Maximum time during which event tracing retry is attempted on buffer + full condition (millliseconds). Setting this environment to non-zero + value effectively blocks the application on buffer full condition. + Setting this environment variable to non-zero values may + significantly affect application timings. Setting this to a negative + value may block the application indefinitely if there is no consumer + emptying the ring buffer. The delay between retry attempts is the + minimum between the specified timeout value and 100ms. This option + can be useful in workloads generating very large trace data + throughput, where blocking the application is an acceptable + trade-off to not discard events. _Use with caution_. ++ +The value `0` means _do not retry_. The value `-1` means _retry forever_. +Value > `0` means a maximum timeout of the given value. ++ +Default: {lttng_ust_blocking_retry_timeout}. + +`LTTNG_UST_WITHOUT_BADDR_STATEDUMP`:: + Prevents `liblttng-ust` from performing a base address state dump + (see the <> section above) if + set to `1`. include::common-footer.txt[]