19cfe06f8SSteven Rostedt /* 29cfe06f8SSteven Rostedt * If TRACE_SYSTEM is defined, that will be the directory created 34e20e3a6SSteven Rostedt (Red Hat) * in the ftrace directory under /sys/kernel/tracing/events/<system> 49cfe06f8SSteven Rostedt * 544ad18e0SSteven Rostedt * The define_trace.h below will also look for a file name of 69cfe06f8SSteven Rostedt * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. 744ad18e0SSteven Rostedt * In this case, it would look for sample.h 89cfe06f8SSteven Rostedt * 944ad18e0SSteven Rostedt * If the header name will be different than the system name 1044ad18e0SSteven Rostedt * (as in this case), then you can override the header name that 1144ad18e0SSteven Rostedt * define_trace.h will look up by defining TRACE_INCLUDE_FILE 129cfe06f8SSteven Rostedt * 1344ad18e0SSteven Rostedt * This file is called trace-events-sample.h but we want the system 1444ad18e0SSteven Rostedt * to be called "sample". Therefore we must define the name of this 1544ad18e0SSteven Rostedt * file: 169cfe06f8SSteven Rostedt * 1744ad18e0SSteven Rostedt * #define TRACE_INCLUDE_FILE trace-events-sample 189cfe06f8SSteven Rostedt * 1944ad18e0SSteven Rostedt * As we do an the bottom of this file. 20d0b6e04aSLi Zefan * 21d0b6e04aSLi Zefan * Notice that TRACE_SYSTEM should be defined outside of #if 22d0b6e04aSLi Zefan * protection, just like TRACE_INCLUDE_FILE. 239cfe06f8SSteven Rostedt */ 249cfe06f8SSteven Rostedt #undef TRACE_SYSTEM 2588920427SSteven Rostedt (Red Hat) #define TRACE_SYSTEM sample-trace 2688920427SSteven Rostedt (Red Hat) 2788920427SSteven Rostedt (Red Hat) /* 2888920427SSteven Rostedt (Red Hat) * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric 2988920427SSteven Rostedt (Red Hat) * and underscore), although it may start with numbers. If for some 3088920427SSteven Rostedt (Red Hat) * reason it is not, you need to add the following lines: 3188920427SSteven Rostedt (Red Hat) */ 3288920427SSteven Rostedt (Red Hat) #undef TRACE_SYSTEM_VAR 3388920427SSteven Rostedt (Red Hat) #define TRACE_SYSTEM_VAR sample_trace 3488920427SSteven Rostedt (Red Hat) /* 3588920427SSteven Rostedt (Red Hat) * But the above is only needed if TRACE_SYSTEM is not alpha-numeric 3688920427SSteven Rostedt (Red Hat) * and underscored. By default, TRACE_SYSTEM_VAR will be equal to 3788920427SSteven Rostedt (Red Hat) * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if 3888920427SSteven Rostedt (Red Hat) * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with 3988920427SSteven Rostedt (Red Hat) * only alpha-numeric and underscores. 4088920427SSteven Rostedt (Red Hat) * 4188920427SSteven Rostedt (Red Hat) * The TRACE_SYSTEM_VAR is only used internally and not visible to 4288920427SSteven Rostedt (Red Hat) * user space. 4388920427SSteven Rostedt (Red Hat) */ 449cfe06f8SSteven Rostedt 459cfe06f8SSteven Rostedt /* 46d0b6e04aSLi Zefan * Notice that this file is not protected like a normal header. 47d0b6e04aSLi Zefan * We also must allow for rereading of this file. The 48d0b6e04aSLi Zefan * 49d0b6e04aSLi Zefan * || defined(TRACE_HEADER_MULTI_READ) 50d0b6e04aSLi Zefan * 51d0b6e04aSLi Zefan * serves this purpose. 52d0b6e04aSLi Zefan */ 53d0b6e04aSLi Zefan #if !defined(_TRACE_EVENT_SAMPLE_H) || defined(TRACE_HEADER_MULTI_READ) 54d0b6e04aSLi Zefan #define _TRACE_EVENT_SAMPLE_H 55d0b6e04aSLi Zefan 56d0b6e04aSLi Zefan /* 57d0b6e04aSLi Zefan * All trace headers should include tracepoint.h, until we finally 58d0b6e04aSLi Zefan * make it into a standard header. 59d0b6e04aSLi Zefan */ 60d0b6e04aSLi Zefan #include <linux/tracepoint.h> 61d0b6e04aSLi Zefan 62d0b6e04aSLi Zefan /* 639cfe06f8SSteven Rostedt * The TRACE_EVENT macro is broken up into 5 parts. 649cfe06f8SSteven Rostedt * 659cfe06f8SSteven Rostedt * name: name of the trace point. This is also how to enable the tracepoint. 669cfe06f8SSteven Rostedt * A function called trace_foo_bar() will be created. 679cfe06f8SSteven Rostedt * 689cfe06f8SSteven Rostedt * proto: the prototype of the function trace_foo_bar() 699cfe06f8SSteven Rostedt * Here it is trace_foo_bar(char *foo, int bar). 709cfe06f8SSteven Rostedt * 719cfe06f8SSteven Rostedt * args: must match the arguments in the prototype. 729cfe06f8SSteven Rostedt * Here it is simply "foo, bar". 739cfe06f8SSteven Rostedt * 749cfe06f8SSteven Rostedt * struct: This defines the way the data will be stored in the ring buffer. 754e20e3a6SSteven Rostedt (Red Hat) * The items declared here become part of a special structure 764e20e3a6SSteven Rostedt (Red Hat) * called "__entry", which can be used in the fast_assign part of the 774e20e3a6SSteven Rostedt (Red Hat) * TRACE_EVENT macro. 789cfe06f8SSteven Rostedt * 794e20e3a6SSteven Rostedt (Red Hat) * Here are the currently defined types you can use: 804e20e3a6SSteven Rostedt (Red Hat) * 814e20e3a6SSteven Rostedt (Red Hat) * __field : Is broken up into type and name. Where type can be any 824e20e3a6SSteven Rostedt (Red Hat) * primitive type (integer, long or pointer). 834e20e3a6SSteven Rostedt (Red Hat) * 844e20e3a6SSteven Rostedt (Red Hat) * __field(int, foo) 854e20e3a6SSteven Rostedt (Red Hat) * 864e20e3a6SSteven Rostedt (Red Hat) * __entry->foo = 5; 874e20e3a6SSteven Rostedt (Red Hat) * 884e20e3a6SSteven Rostedt (Red Hat) * __field_struct : This can be any static complex data type (struct, union 894e20e3a6SSteven Rostedt (Red Hat) * but not an array). Be careful using complex types, as each 904e20e3a6SSteven Rostedt (Red Hat) * event is limited in size, and copying large amounts of data 914e20e3a6SSteven Rostedt (Red Hat) * into the ring buffer can slow things down. 924e20e3a6SSteven Rostedt (Red Hat) * 934e20e3a6SSteven Rostedt (Red Hat) * __field_struct(struct bar, foo) 944e20e3a6SSteven Rostedt (Red Hat) * 954e20e3a6SSteven Rostedt (Red Hat) * __entry->bar.x = y; 964e20e3a6SSteven Rostedt (Red Hat) 974e20e3a6SSteven Rostedt (Red Hat) * __array: There are three fields (type, name, size). The type is the 984e20e3a6SSteven Rostedt (Red Hat) * type of elements in teh array, the name is the name of the array. 994e20e3a6SSteven Rostedt (Red Hat) * size is the number of items in the array (not the total size). 1004e20e3a6SSteven Rostedt (Red Hat) * 1014e20e3a6SSteven Rostedt (Red Hat) * __array( char, foo, 10) is the same as saying: char foo[10]; 1024e20e3a6SSteven Rostedt (Red Hat) * 1034e20e3a6SSteven Rostedt (Red Hat) * Assigning arrays can be done like any array: 1044e20e3a6SSteven Rostedt (Red Hat) * 1054e20e3a6SSteven Rostedt (Red Hat) * __entry->foo[0] = 'a'; 1064e20e3a6SSteven Rostedt (Red Hat) * 1074e20e3a6SSteven Rostedt (Red Hat) * memcpy(__entry->foo, bar, 10); 1084e20e3a6SSteven Rostedt (Red Hat) * 1094e20e3a6SSteven Rostedt (Red Hat) * __dynamic_array: This is similar to array, but can vary is size from 1104e20e3a6SSteven Rostedt (Red Hat) * instance to instance of the tracepoint being called. 1114e20e3a6SSteven Rostedt (Red Hat) * Like __array, this too has three elements (type, name, size); 1124e20e3a6SSteven Rostedt (Red Hat) * type is the type of the element, name is the name of the array. 1134e20e3a6SSteven Rostedt (Red Hat) * The size is different than __array. It is not a static number, 1144e20e3a6SSteven Rostedt (Red Hat) * but the algorithm to figure out the length of the array for the 1154e20e3a6SSteven Rostedt (Red Hat) * specific instance of tracepoint. Again, size is the numebr of 1164e20e3a6SSteven Rostedt (Red Hat) * items in the array, not the total length in bytes. 1174e20e3a6SSteven Rostedt (Red Hat) * 1184e20e3a6SSteven Rostedt (Red Hat) * __dynamic_array( int, foo, bar) is similar to: int foo[bar]; 1194e20e3a6SSteven Rostedt (Red Hat) * 1204e20e3a6SSteven Rostedt (Red Hat) * Note, unlike arrays, you must use the __get_dynamic_array() macro 1214e20e3a6SSteven Rostedt (Red Hat) * to access the array. 1224e20e3a6SSteven Rostedt (Red Hat) * 1234e20e3a6SSteven Rostedt (Red Hat) * memcpy(__get_dynamic_array(foo), bar, 10); 1244e20e3a6SSteven Rostedt (Red Hat) * 1254e20e3a6SSteven Rostedt (Red Hat) * Notice, that "__entry" is not needed here. 1264e20e3a6SSteven Rostedt (Red Hat) * 1274e20e3a6SSteven Rostedt (Red Hat) * __string: This is a special kind of __dynamic_array. It expects to 1284e20e3a6SSteven Rostedt (Red Hat) * have a nul terminated character array passed to it (it allows 1294e20e3a6SSteven Rostedt (Red Hat) * for NULL too, which would be converted into "(null)"). __string 1304e20e3a6SSteven Rostedt (Red Hat) * takes two paramenter (name, src), where name is the name of 1314e20e3a6SSteven Rostedt (Red Hat) * the string saved, and src is the string to copy into the 1324e20e3a6SSteven Rostedt (Red Hat) * ring buffer. 1334e20e3a6SSteven Rostedt (Red Hat) * 1344e20e3a6SSteven Rostedt (Red Hat) * __string(foo, bar) is similar to: strcpy(foo, bar) 1354e20e3a6SSteven Rostedt (Red Hat) * 1364e20e3a6SSteven Rostedt (Red Hat) * To assign a string, use the helper macro __assign_str(). 1374e20e3a6SSteven Rostedt (Red Hat) * 1384e20e3a6SSteven Rostedt (Red Hat) * __assign_str(foo, bar); 1394e20e3a6SSteven Rostedt (Red Hat) * 1404e20e3a6SSteven Rostedt (Red Hat) * In most cases, the __assign_str() macro will take the same 1414e20e3a6SSteven Rostedt (Red Hat) * parameters as the __string() macro had to declare the string. 1424e20e3a6SSteven Rostedt (Red Hat) * 1434e20e3a6SSteven Rostedt (Red Hat) * __bitmask: This is another kind of __dynamic_array, but it expects 1444e20e3a6SSteven Rostedt (Red Hat) * an array of longs, and the number of bits to parse. It takes 1454e20e3a6SSteven Rostedt (Red Hat) * two parameters (name, nr_bits), where name is the name of the 1464e20e3a6SSteven Rostedt (Red Hat) * bitmask to save, and the nr_bits is the number of bits to record. 1474e20e3a6SSteven Rostedt (Red Hat) * 1484e20e3a6SSteven Rostedt (Red Hat) * __bitmask(target_cpu, nr_cpumask_bits) 1494e20e3a6SSteven Rostedt (Red Hat) * 1504e20e3a6SSteven Rostedt (Red Hat) * To assign a bitmask, use the __assign_bitmask() helper macro. 1514e20e3a6SSteven Rostedt (Red Hat) * 1524e20e3a6SSteven Rostedt (Red Hat) * __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits); 1534e20e3a6SSteven Rostedt (Red Hat) * 1549cfe06f8SSteven Rostedt * 1559cfe06f8SSteven Rostedt * fast_assign: This is a C like function that is used to store the items 1564e20e3a6SSteven Rostedt (Red Hat) * into the ring buffer. A special variable called "__entry" will be the 1574e20e3a6SSteven Rostedt (Red Hat) * structure that points into the ring buffer and has the same fields as 1584e20e3a6SSteven Rostedt (Red Hat) * described by the struct part of TRACE_EVENT above. 1599cfe06f8SSteven Rostedt * 1609cfe06f8SSteven Rostedt * printk: This is a way to print out the data in pretty print. This is 1619cfe06f8SSteven Rostedt * useful if the system crashes and you are logging via a serial line, 1629cfe06f8SSteven Rostedt * the data can be printed to the console using this "printk" method. 1634e20e3a6SSteven Rostedt (Red Hat) * This is also used to print out the data from the trace files. 1644e20e3a6SSteven Rostedt (Red Hat) * Again, the __entry macro is used to access the data from the ring buffer. 1654e20e3a6SSteven Rostedt (Red Hat) * 1664e20e3a6SSteven Rostedt (Red Hat) * Note, __dynamic_array, __string, and __bitmask require special helpers 1674e20e3a6SSteven Rostedt (Red Hat) * to access the data. 1684e20e3a6SSteven Rostedt (Red Hat) * 1694e20e3a6SSteven Rostedt (Red Hat) * For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo) 1704e20e3a6SSteven Rostedt (Red Hat) * Use __get_dynamic_array_len(foo) to get the length of the array 1714e20e3a6SSteven Rostedt (Red Hat) * saved. 1724e20e3a6SSteven Rostedt (Red Hat) * 1734e20e3a6SSteven Rostedt (Red Hat) * For __string(foo, bar) use __get_str(foo) 1744e20e3a6SSteven Rostedt (Red Hat) * 1754e20e3a6SSteven Rostedt (Red Hat) * For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus) 1764e20e3a6SSteven Rostedt (Red Hat) * 1779cfe06f8SSteven Rostedt * 1789cfe06f8SSteven Rostedt * Note, that for both the assign and the printk, __entry is the handler 1799cfe06f8SSteven Rostedt * to the data structure in the ring buffer, and is defined by the 1809cfe06f8SSteven Rostedt * TP_STRUCT__entry. 1819cfe06f8SSteven Rostedt */ 1824e20e3a6SSteven Rostedt (Red Hat) 1834e20e3a6SSteven Rostedt (Red Hat) /* 1844e20e3a6SSteven Rostedt (Red Hat) * It is OK to have helper functions in the file, but they need to be protected 1854e20e3a6SSteven Rostedt (Red Hat) * from being defined more than once. Remember, this file gets included more 1864e20e3a6SSteven Rostedt (Red Hat) * than once. 1874e20e3a6SSteven Rostedt (Red Hat) */ 1884e20e3a6SSteven Rostedt (Red Hat) #ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS 1894e20e3a6SSteven Rostedt (Red Hat) #define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS 1904e20e3a6SSteven Rostedt (Red Hat) static inline int __length_of(const int *list) 1914e20e3a6SSteven Rostedt (Red Hat) { 1924e20e3a6SSteven Rostedt (Red Hat) int i; 1934e20e3a6SSteven Rostedt (Red Hat) 1944e20e3a6SSteven Rostedt (Red Hat) if (!list) 1954e20e3a6SSteven Rostedt (Red Hat) return 0; 1964e20e3a6SSteven Rostedt (Red Hat) 1974e20e3a6SSteven Rostedt (Red Hat) for (i = 0; list[i]; i++) 1984e20e3a6SSteven Rostedt (Red Hat) ; 1994e20e3a6SSteven Rostedt (Red Hat) return i; 2004e20e3a6SSteven Rostedt (Red Hat) } 2014e20e3a6SSteven Rostedt (Red Hat) #endif 2024e20e3a6SSteven Rostedt (Red Hat) 2039cfe06f8SSteven Rostedt TRACE_EVENT(foo_bar, 2049cfe06f8SSteven Rostedt 2054e20e3a6SSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar, const int *lst, 2064e20e3a6SSteven Rostedt (Red Hat) const char *string, const struct cpumask *mask), 2079cfe06f8SSteven Rostedt 2084e20e3a6SSteven Rostedt (Red Hat) TP_ARGS(foo, bar, lst, string, mask), 2099cfe06f8SSteven Rostedt 2109cfe06f8SSteven Rostedt TP_STRUCT__entry( 2119cfe06f8SSteven Rostedt __array( char, foo, 10 ) 2129cfe06f8SSteven Rostedt __field( int, bar ) 2134e20e3a6SSteven Rostedt (Red Hat) __dynamic_array(int, list, __length_of(lst)) 2144e20e3a6SSteven Rostedt (Red Hat) __string( str, string ) 2154e20e3a6SSteven Rostedt (Red Hat) __bitmask( cpus, num_possible_cpus() ) 2169cfe06f8SSteven Rostedt ), 2179cfe06f8SSteven Rostedt 2189cfe06f8SSteven Rostedt TP_fast_assign( 219d8fae2f6SZhao Hongjiang strlcpy(__entry->foo, foo, 10); 2209cfe06f8SSteven Rostedt __entry->bar = bar; 2214e20e3a6SSteven Rostedt (Red Hat) memcpy(__get_dynamic_array(list), lst, 2224e20e3a6SSteven Rostedt (Red Hat) __length_of(lst) * sizeof(int)); 2234e20e3a6SSteven Rostedt (Red Hat) __assign_str(str, string); 2244e20e3a6SSteven Rostedt (Red Hat) __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); 2259cfe06f8SSteven Rostedt ), 2269cfe06f8SSteven Rostedt 2274e20e3a6SSteven Rostedt (Red Hat) TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar, 2284e20e3a6SSteven Rostedt (Red Hat) __print_array(__get_dynamic_array(list), 2294e20e3a6SSteven Rostedt (Red Hat) __get_dynamic_array_len(list), 2304e20e3a6SSteven Rostedt (Red Hat) sizeof(int)), 2314e20e3a6SSteven Rostedt (Red Hat) __get_str(str), __get_bitmask(cpus)) 2329cfe06f8SSteven Rostedt ); 233c4c7eb29SSteven Rostedt (Red Hat) 234c4c7eb29SSteven Rostedt (Red Hat) /* 235c4c7eb29SSteven Rostedt (Red Hat) * There may be a case where a tracepoint should only be called if 236c4c7eb29SSteven Rostedt (Red Hat) * some condition is set. Otherwise the tracepoint should not be called. 237c4c7eb29SSteven Rostedt (Red Hat) * But to do something like: 238c4c7eb29SSteven Rostedt (Red Hat) * 239c4c7eb29SSteven Rostedt (Red Hat) * if (cond) 240c4c7eb29SSteven Rostedt (Red Hat) * trace_foo(); 241c4c7eb29SSteven Rostedt (Red Hat) * 242c4c7eb29SSteven Rostedt (Red Hat) * Would cause a little overhead when tracing is not enabled, and that 243c4c7eb29SSteven Rostedt (Red Hat) * overhead, even if small, is not something we want. As tracepoints 244c4c7eb29SSteven Rostedt (Red Hat) * use static branch (aka jump_labels), where no branch is taken to 245c4c7eb29SSteven Rostedt (Red Hat) * skip the tracepoint when not enabled, and a jmp is placed to jump 246c4c7eb29SSteven Rostedt (Red Hat) * to the tracepoint code when it is enabled, having a if statement 247c4c7eb29SSteven Rostedt (Red Hat) * nullifies that optimization. It would be nice to place that 248c4c7eb29SSteven Rostedt (Red Hat) * condition within the static branch. This is where TRACE_EVENT_CONDITION 249c4c7eb29SSteven Rostedt (Red Hat) * comes in. 250c4c7eb29SSteven Rostedt (Red Hat) * 251c4c7eb29SSteven Rostedt (Red Hat) * TRACE_EVENT_CONDITION() is just like TRACE_EVENT, except it adds another 252c4c7eb29SSteven Rostedt (Red Hat) * parameter just after args. Where TRACE_EVENT has: 253c4c7eb29SSteven Rostedt (Red Hat) * 254c4c7eb29SSteven Rostedt (Red Hat) * TRACE_EVENT(name, proto, args, struct, assign, printk) 255c4c7eb29SSteven Rostedt (Red Hat) * 256c4c7eb29SSteven Rostedt (Red Hat) * the CONDITION version has: 257c4c7eb29SSteven Rostedt (Red Hat) * 258c4c7eb29SSteven Rostedt (Red Hat) * TRACE_EVENT_CONDITION(name, proto, args, cond, struct, assign, printk) 259c4c7eb29SSteven Rostedt (Red Hat) * 260c4c7eb29SSteven Rostedt (Red Hat) * Everything is the same as TRACE_EVENT except for the new cond. Think 261c4c7eb29SSteven Rostedt (Red Hat) * of the cond variable as: 262c4c7eb29SSteven Rostedt (Red Hat) * 263c4c7eb29SSteven Rostedt (Red Hat) * if (cond) 264c4c7eb29SSteven Rostedt (Red Hat) * trace_foo_bar_with_cond(); 265c4c7eb29SSteven Rostedt (Red Hat) * 266c4c7eb29SSteven Rostedt (Red Hat) * Except that the logic for the if branch is placed after the static branch. 267c4c7eb29SSteven Rostedt (Red Hat) * That is, the if statement that processes the condition will not be 268c4c7eb29SSteven Rostedt (Red Hat) * executed unless that traecpoint is enabled. Otherwise it still remains 269c4c7eb29SSteven Rostedt (Red Hat) * a nop. 270c4c7eb29SSteven Rostedt (Red Hat) */ 271c4c7eb29SSteven Rostedt (Red Hat) TRACE_EVENT_CONDITION(foo_bar_with_cond, 272c4c7eb29SSteven Rostedt (Red Hat) 273c4c7eb29SSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 274c4c7eb29SSteven Rostedt (Red Hat) 275c4c7eb29SSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 276c4c7eb29SSteven Rostedt (Red Hat) 277c4c7eb29SSteven Rostedt (Red Hat) TP_CONDITION(!(bar % 10)), 278c4c7eb29SSteven Rostedt (Red Hat) 279c4c7eb29SSteven Rostedt (Red Hat) TP_STRUCT__entry( 280c4c7eb29SSteven Rostedt (Red Hat) __string( foo, foo ) 281c4c7eb29SSteven Rostedt (Red Hat) __field( int, bar ) 282c4c7eb29SSteven Rostedt (Red Hat) ), 283c4c7eb29SSteven Rostedt (Red Hat) 284c4c7eb29SSteven Rostedt (Red Hat) TP_fast_assign( 285c4c7eb29SSteven Rostedt (Red Hat) __assign_str(foo, foo); 286c4c7eb29SSteven Rostedt (Red Hat) __entry->bar = bar; 287c4c7eb29SSteven Rostedt (Red Hat) ), 288c4c7eb29SSteven Rostedt (Red Hat) 289c4c7eb29SSteven Rostedt (Red Hat) TP_printk("foo %s %d", __get_str(foo), __entry->bar) 290c4c7eb29SSteven Rostedt (Red Hat) ); 2916adc13f8SSteven Rostedt (Red Hat) 2926adc13f8SSteven Rostedt (Red Hat) void foo_bar_reg(void); 2936adc13f8SSteven Rostedt (Red Hat) void foo_bar_unreg(void); 2946adc13f8SSteven Rostedt (Red Hat) 2956adc13f8SSteven Rostedt (Red Hat) /* 2966adc13f8SSteven Rostedt (Red Hat) * Now in the case that some function needs to be called when the 2976adc13f8SSteven Rostedt (Red Hat) * tracepoint is enabled and/or when it is disabled, the 2986adc13f8SSteven Rostedt (Red Hat) * TRACE_EVENT_FN() serves this purpose. This is just like TRACE_EVENT() 2996adc13f8SSteven Rostedt (Red Hat) * but adds two more parameters at the end: 3006adc13f8SSteven Rostedt (Red Hat) * 3016adc13f8SSteven Rostedt (Red Hat) * TRACE_EVENT_FN( name, proto, args, struct, assign, printk, reg, unreg) 3026adc13f8SSteven Rostedt (Red Hat) * 3036adc13f8SSteven Rostedt (Red Hat) * reg and unreg are functions with the prototype of: 3046adc13f8SSteven Rostedt (Red Hat) * 3056adc13f8SSteven Rostedt (Red Hat) * void reg(void) 3066adc13f8SSteven Rostedt (Red Hat) * 3076adc13f8SSteven Rostedt (Red Hat) * The reg function gets called before the tracepoint is enabled, and 3086adc13f8SSteven Rostedt (Red Hat) * the unreg function gets called after the tracepoint is disabled. 3096adc13f8SSteven Rostedt (Red Hat) * 3106adc13f8SSteven Rostedt (Red Hat) * Note, reg and unreg are allowed to be NULL. If you only need to 3116adc13f8SSteven Rostedt (Red Hat) * call a function before enabling, or after disabling, just set one 3126adc13f8SSteven Rostedt (Red Hat) * function and pass in NULL for the other parameter. 3136adc13f8SSteven Rostedt (Red Hat) */ 3146adc13f8SSteven Rostedt (Red Hat) TRACE_EVENT_FN(foo_bar_with_fn, 3156adc13f8SSteven Rostedt (Red Hat) 3166adc13f8SSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 3176adc13f8SSteven Rostedt (Red Hat) 3186adc13f8SSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 3196adc13f8SSteven Rostedt (Red Hat) 3206adc13f8SSteven Rostedt (Red Hat) TP_STRUCT__entry( 3216adc13f8SSteven Rostedt (Red Hat) __string( foo, foo ) 3226adc13f8SSteven Rostedt (Red Hat) __field( int, bar ) 3236adc13f8SSteven Rostedt (Red Hat) ), 3246adc13f8SSteven Rostedt (Red Hat) 3256adc13f8SSteven Rostedt (Red Hat) TP_fast_assign( 3266adc13f8SSteven Rostedt (Red Hat) __assign_str(foo, foo); 3276adc13f8SSteven Rostedt (Red Hat) __entry->bar = bar; 3286adc13f8SSteven Rostedt (Red Hat) ), 3296adc13f8SSteven Rostedt (Red Hat) 3306adc13f8SSteven Rostedt (Red Hat) TP_printk("foo %s %d", __get_str(foo), __entry->bar), 3316adc13f8SSteven Rostedt (Red Hat) 3326adc13f8SSteven Rostedt (Red Hat) foo_bar_reg, foo_bar_unreg 3336adc13f8SSteven Rostedt (Red Hat) ); 3346adc13f8SSteven Rostedt (Red Hat) 3357496946aSSteven Rostedt (Red Hat) /* 3367496946aSSteven Rostedt (Red Hat) * Each TRACE_EVENT macro creates several helper functions to produce 3377496946aSSteven Rostedt (Red Hat) * the code to add the tracepoint, create the files in the trace 3387496946aSSteven Rostedt (Red Hat) * directory, hook it to perf, assign the values and to print out 3397496946aSSteven Rostedt (Red Hat) * the raw data from the ring buffer. To prevent too much bloat, 3407496946aSSteven Rostedt (Red Hat) * if there are more than one tracepoint that uses the same format 3417496946aSSteven Rostedt (Red Hat) * for the proto, args, struct, assign and printk, and only the name 3427496946aSSteven Rostedt (Red Hat) * is different, it is highly recommended to use the DECLARE_EVENT_CLASS 3437496946aSSteven Rostedt (Red Hat) * 3447496946aSSteven Rostedt (Red Hat) * DECLARE_EVENT_CLASS() macro creates most of the functions for the 3457496946aSSteven Rostedt (Red Hat) * tracepoint. Then DEFINE_EVENT() is use to hook a tracepoint to those 3467496946aSSteven Rostedt (Red Hat) * functions. This DEFINE_EVENT() is an instance of the class and can 3477496946aSSteven Rostedt (Red Hat) * be enabled and disabled separately from other events (either TRACE_EVENT 3487496946aSSteven Rostedt (Red Hat) * or other DEFINE_EVENT()s). 3497496946aSSteven Rostedt (Red Hat) * 3507496946aSSteven Rostedt (Red Hat) * Note, TRACE_EVENT() itself is simply defined as: 3517496946aSSteven Rostedt (Red Hat) * 3527496946aSSteven Rostedt (Red Hat) * #define TRACE_EVENT(name, proto, args, tstruct, assign, printk) \ 3537496946aSSteven Rostedt (Red Hat) * DEFINE_EVENT_CLASS(name, proto, args, tstruct, assign, printk); \ 3547496946aSSteven Rostedt (Red Hat) * DEFINE_EVENT(name, name, proto, args) 3557496946aSSteven Rostedt (Red Hat) * 3567496946aSSteven Rostedt (Red Hat) * The DEFINE_EVENT() also can be declared with conditions and reg functions: 3577496946aSSteven Rostedt (Red Hat) * 3587496946aSSteven Rostedt (Red Hat) * DEFINE_EVENT_CONDITION(template, name, proto, args, cond); 3597496946aSSteven Rostedt (Red Hat) * DEFINE_EVENT_FN(template, name, proto, args, reg, unreg); 3607496946aSSteven Rostedt (Red Hat) */ 3617496946aSSteven Rostedt (Red Hat) DECLARE_EVENT_CLASS(foo_template, 3627496946aSSteven Rostedt (Red Hat) 3637496946aSSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 3647496946aSSteven Rostedt (Red Hat) 3657496946aSSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 3667496946aSSteven Rostedt (Red Hat) 3677496946aSSteven Rostedt (Red Hat) TP_STRUCT__entry( 3687496946aSSteven Rostedt (Red Hat) __string( foo, foo ) 3697496946aSSteven Rostedt (Red Hat) __field( int, bar ) 3707496946aSSteven Rostedt (Red Hat) ), 3717496946aSSteven Rostedt (Red Hat) 3727496946aSSteven Rostedt (Red Hat) TP_fast_assign( 3737496946aSSteven Rostedt (Red Hat) __assign_str(foo, foo); 3747496946aSSteven Rostedt (Red Hat) __entry->bar = bar; 3757496946aSSteven Rostedt (Red Hat) ), 3767496946aSSteven Rostedt (Red Hat) 3777496946aSSteven Rostedt (Red Hat) TP_printk("foo %s %d", __get_str(foo), __entry->bar) 3787496946aSSteven Rostedt (Red Hat) ); 3797496946aSSteven Rostedt (Red Hat) 3807496946aSSteven Rostedt (Red Hat) /* 3817496946aSSteven Rostedt (Red Hat) * Here's a better way for the previous samples (except, the first 3827496946aSSteven Rostedt (Red Hat) * exmaple had more fields and could not be used here). 3837496946aSSteven Rostedt (Red Hat) */ 3847496946aSSteven Rostedt (Red Hat) DEFINE_EVENT(foo_template, foo_with_template_simple, 3857496946aSSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 3867496946aSSteven Rostedt (Red Hat) TP_ARGS(foo, bar)); 3877496946aSSteven Rostedt (Red Hat) 3887496946aSSteven Rostedt (Red Hat) DEFINE_EVENT_CONDITION(foo_template, foo_with_template_cond, 3897496946aSSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 3907496946aSSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 3917496946aSSteven Rostedt (Red Hat) TP_CONDITION(!(bar % 8))); 3927496946aSSteven Rostedt (Red Hat) 3937496946aSSteven Rostedt (Red Hat) 3947496946aSSteven Rostedt (Red Hat) DEFINE_EVENT_FN(foo_template, foo_with_template_fn, 3957496946aSSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 3967496946aSSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 3977496946aSSteven Rostedt (Red Hat) foo_bar_reg, foo_bar_unreg); 3987496946aSSteven Rostedt (Red Hat) 3997496946aSSteven Rostedt (Red Hat) /* 4007496946aSSteven Rostedt (Red Hat) * Anytime two events share basically the same values and have 4017496946aSSteven Rostedt (Red Hat) * the same output, use the DECLARE_EVENT_CLASS() and DEFINE_EVENT() 4027496946aSSteven Rostedt (Red Hat) * when ever possible. 4037496946aSSteven Rostedt (Red Hat) */ 4047496946aSSteven Rostedt (Red Hat) 4057496946aSSteven Rostedt (Red Hat) /* 4067496946aSSteven Rostedt (Red Hat) * If the event is similar to the DECLARE_EVENT_CLASS, but you need 4077496946aSSteven Rostedt (Red Hat) * to have a different output, then use DEFINE_EVENT_PRINT() which 4087496946aSSteven Rostedt (Red Hat) * lets you override the TP_printk() of the class. 4097496946aSSteven Rostedt (Red Hat) */ 4107496946aSSteven Rostedt (Red Hat) 4117496946aSSteven Rostedt (Red Hat) DEFINE_EVENT_PRINT(foo_template, foo_with_template_print, 4127496946aSSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar), 4137496946aSSteven Rostedt (Red Hat) TP_ARGS(foo, bar), 4147496946aSSteven Rostedt (Red Hat) TP_printk("bar %s %d", __get_str(foo), __entry->bar)); 4157496946aSSteven Rostedt (Red Hat) 4169cfe06f8SSteven Rostedt #endif 4179cfe06f8SSteven Rostedt 4189cfe06f8SSteven Rostedt /***** NOTICE! The #if protection ends here. *****/ 4199cfe06f8SSteven Rostedt 4209cfe06f8SSteven Rostedt 4219cfe06f8SSteven Rostedt /* 4229cfe06f8SSteven Rostedt * There are several ways I could have done this. If I left out the 4239cfe06f8SSteven Rostedt * TRACE_INCLUDE_PATH, then it would default to the kernel source 4249cfe06f8SSteven Rostedt * include/trace/events directory. 4259cfe06f8SSteven Rostedt * 4269cfe06f8SSteven Rostedt * I could specify a path from the define_trace.h file back to this 4279cfe06f8SSteven Rostedt * file. 4289cfe06f8SSteven Rostedt * 4299cfe06f8SSteven Rostedt * #define TRACE_INCLUDE_PATH ../../samples/trace_events 4309cfe06f8SSteven Rostedt * 43144ad18e0SSteven Rostedt * But the safest and easiest way to simply make it use the directory 43244ad18e0SSteven Rostedt * that the file is in is to add in the Makefile: 4339cfe06f8SSteven Rostedt * 43444ad18e0SSteven Rostedt * CFLAGS_trace-events-sample.o := -I$(src) 4359cfe06f8SSteven Rostedt * 4369cfe06f8SSteven Rostedt * This will make sure the current path is part of the include 43744ad18e0SSteven Rostedt * structure for our file so that define_trace.h can find it. 4389cfe06f8SSteven Rostedt * 4399cfe06f8SSteven Rostedt * I could have made only the top level directory the include: 4409cfe06f8SSteven Rostedt * 4419cfe06f8SSteven Rostedt * CFLAGS_trace-events-sample.o := -I$(PWD) 4429cfe06f8SSteven Rostedt * 4439cfe06f8SSteven Rostedt * And then let the path to this directory be the TRACE_INCLUDE_PATH: 4449cfe06f8SSteven Rostedt * 4459cfe06f8SSteven Rostedt * #define TRACE_INCLUDE_PATH samples/trace_events 4469cfe06f8SSteven Rostedt * 44744ad18e0SSteven Rostedt * But then if something defines "samples" or "trace_events" as a macro 44844ad18e0SSteven Rostedt * then we could risk that being converted too, and give us an unexpected 4499cfe06f8SSteven Rostedt * result. 4509cfe06f8SSteven Rostedt */ 4519cfe06f8SSteven Rostedt #undef TRACE_INCLUDE_PATH 45271e1c8acSSteven Rostedt #undef TRACE_INCLUDE_FILE 4539cfe06f8SSteven Rostedt #define TRACE_INCLUDE_PATH . 45471e1c8acSSteven Rostedt /* 45571e1c8acSSteven Rostedt * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal 45671e1c8acSSteven Rostedt */ 45771e1c8acSSteven Rostedt #define TRACE_INCLUDE_FILE trace-events-sample 4589cfe06f8SSteven Rostedt #include <trace/define_trace.h> 459