X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=include%2Fust%2Ftracepoint.h;h=e7c6b198bc464bde94990623df48912b4af51a68;hb=e9f37b4cb3e2485b949083307aadfc4bda56ce96;hp=b659050a0231d3646cda7fd40ccb94fde043cf4c;hpb=e90908999722d651b3113c121ba28a62b52d229c;p=lttng-ust.git diff --git a/include/ust/tracepoint.h b/include/ust/tracepoint.h index b659050a..e7c6b198 100644 --- a/include/ust/tracepoint.h +++ b/include/ust/tracepoint.h @@ -45,28 +45,6 @@ struct tracepoint { */ #define tracepoint(name, args...) __trace_##name(args) -/* - * Library should be made known to libust by declaring TRACEPOINT_LIB in - * the source file. (Usually at the end of the file, in the outermost - * scope). - */ -#define TRACEPOINT_LIB \ - extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \ - extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \ - static struct tracepoint * __tracepoint_ptr_dummy \ - __attribute__((used, section("__tracepoints_ptrs"))); \ - static void __attribute__((constructor)) __tracepoints__init(void) \ - { \ - tracepoint_register_lib(__start___tracepoints_ptrs, \ - __stop___tracepoints_ptrs - \ - __start___tracepoints_ptrs); \ - } \ - \ - static void __attribute__((destructor)) __tracepoints__destroy(void) \ - { \ - tracepoint_unregister_lib(__start___tracepoints_ptrs); \ - } - /* * it_func[0] is never NULL because there is at least one element in the array * when the array itself is non NULL. @@ -182,28 +160,79 @@ int __tracepoint_probe_register(const char *name, void *probe, void *data); extern int __tracepoint_probe_unregister(const char *name, void *probe, void *data); -struct tracepoint_lib { - struct tracepoint * const *tracepoints_start; - int tracepoints_count; - struct cds_list_head list; -}; - extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, int tracepoints_count); extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); +/* + * These weak symbols, the constructor, and destructor take care of + * registering only _one_ instance of the tracepoints per shared-ojbect + * (or for the whole main program). + */ +extern struct tracepoint * const __start___tracepoints_ptrs[] + __attribute__((weak, visibility("hidden"))); +extern struct tracepoint * const __stop___tracepoints_ptrs[] + __attribute__((weak, visibility("hidden"))); +int __tracepoint_registered + __attribute__((weak, visibility("hidden"))); + +static void __attribute__((constructor)) __tracepoints__init(void) +{ + if (__tracepoint_registered++) + return; + tracepoint_register_lib(__start___tracepoints_ptrs, + __stop___tracepoints_ptrs - + __start___tracepoints_ptrs); +} + +static void __attribute__((destructor)) __tracepoints__destroy(void) +{ + if (--__tracepoint_registered) + return; + tracepoint_unregister_lib(__start___tracepoints_ptrs); +} #ifndef TRACEPOINT_EVENT /* - * For use with the TRACEPOINT_EVENT macro: + * Usage of the TRACEPOINT_EVENT macro: + * + * In short, an example: + * + * TRACEPOINT_EVENT(< [com_company_]project_[component_]event >, + * TP_PROTO(int arg0, void *arg1, char *string, size_t strlen, + * long *arg4, size_t arg4_len), + * TP_ARGS(arg0, arg1, string, strlen, arg4, arg4_len), + * TP_FIELDS( + * + * * Integer, printed in base 10 * + * ctf_integer(int, field_a, arg0) + * + * * Integer, printed with 0x base 16 * + * ctf_integer_hex(unsigned long, field_d, arg1) + * + * * Array Sequence, printed as UTF8-encoded array of bytes * + * ctf_array_text(char, field_b, string, FIXED_LEN) + * ctf_sequence_text(char, field_c, string, size_t, strlen) + * + * * String, printed as UTF8-encoded string * + * ctf_string(field_e, string) + * + * * Array sequence of signed integer values * + * ctf_array(long, field_f, arg4, FIXED_LEN4) + * ctf_sequence(long, field_g, arg4, size_t, arg4_len) + * ) + * ) + * + * In more detail: * * We define a tracepoint, its arguments, and its 'fast binary record' * layout. * * Firstly, name your tracepoint via TRACEPOINT_EVENT(name, * + * The name should be a proper C99 identifier. * The "name" MUST follow these rules to ensure no namespace clash * occurs: * @@ -217,8 +246,10 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); * project_event * * Where "project" is the name of the project, - * "component" is the name of the project component where the - * tracepoint is located (optional), + * "component" is the name of the project component (which may + * include several levels of sub-components, e.g. + * ...component_subcomponent_...) where the tracepoint is located + * (optional), * "event" is the name of the tracepoint event. * * For projects issued from a single company wishing to advertise that @@ -232,8 +263,10 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); * * Where "company" is the name of the company, * "project" is the name of the project, - * "component" is the name of the project component where the - * tracepoint is located (optional), + * "component" is the name of the project component (which may + * include several levels of sub-components, e.g. + * ...component_subcomponent_...) where the tracepoint is located + * (optional), * "event" is the name of the tracepoint event. * * @@ -295,6 +328,13 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); * ctf_integer(int, next_prio, next->prio) * ) * ) + * + * Do _NOT_ add comma (,) nor semicolon (;) after the TRACEPOINT_EVENT + * declaration. + * + * The TRACEPOINT_SYSTEM must be defined when declaring a + * TRACEPOINT_EVENT. See ust/tracepoint-event.h for information about + * usage of other macros controlling TRACEPOINT_EVENT. */ #define TRACEPOINT_EVENT(name, proto, args, fields) \ @@ -316,4 +356,61 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); #endif /* #ifndef TRACEPOINT_EVENT */ +#ifndef TRACEPOINT_LOGLEVEL + +/* + * Tracepoint Loglevel Declaration Facility + * + * This is a place-holder the tracepoint loglevel declaration, + * overridden by the tracer implementation. + * + * Typical use of these loglevels: + * + * 1) Declare the mapping between loglevel names and an integer values + * within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple. + * Do _NOT_ add comma (,) nor semicolon (;) between the + * TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor + * semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration. The + * name should be a proper C99 identifier. + * + * TRACEPOINT_LOGLEVEL_ENUM( + * TP_LOGLEVEL( < loglevel_name >, < value > ) + * TP_LOGLEVEL( < loglevel_name >, < value > ) + * ... + * ) + * + * e.g.: + * + * TRACEPOINT_LOGLEVEL_ENUM( + * TP_LOGLEVEL(LOG_EMERG, 0) + * TP_LOGLEVEL(LOG_ALERT, 1) + * TP_LOGLEVEL(LOG_CRIT, 2) + * TP_LOGLEVEL(LOG_ERR, 3) + * TP_LOGLEVEL(LOG_WARNING, 4) + * TP_LOGLEVEL(LOG_NOTICE, 5) + * TP_LOGLEVEL(LOG_INFO, 6) + * TP_LOGLEVEL(LOG_DEBUG, 7) + * ) + * + * 2) Then, declare tracepoint loglevels for tracepoints. A + * TRACEPOINT_EVENT should be declared prior to the the + * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field + * is the name of the tracepoint, the second field is the loglevel + * name. + * + * TRACEPOINT_LOGLEVEL(< [com_company_]project_[component_]event >, + * < loglevel_name >) + * + * The TRACEPOINT_SYSTEM must be defined when declaring a + * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint + * loglevel enumeration apply to the entire TRACEPOINT_SYSTEM. Only one + * tracepoint loglevel enumeration should be declared per tracepoint + * system. + */ + +#define TRACEPOINT_LOGLEVEL_ENUM() +#define TRACEPOINT_LOGLEVEL(name, loglevel) + +#endif /* #ifndef TRACEPOINT_LOGLEVEL */ + #endif /* _UST_TRACEPOINT_H */