Mark Allyn | ff3d9c3 | 2011-12-28 17:37:59 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * If TRACE_SYSTEM is defined, that will be the directory created |
| 3 | * in the ftrace directory under /sys/kernel/debug/tracing/events/<system> |
| 4 | * |
| 5 | * The define_trace.h below will also look for a file name of |
| 6 | * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. |
| 7 | * In this case, it would look for sample.h |
| 8 | * |
| 9 | * If the header name will be different than the system name |
| 10 | * (as in this case), then you can override the header name that |
| 11 | * define_trace.h will look up by defining TRACE_INCLUDE_FILE |
| 12 | * |
| 13 | * This file is called trace-events-sample.h but we want the system |
| 14 | * to be called "sample". Therefore we must define the name of this |
| 15 | * file: |
| 16 | * |
| 17 | * #define TRACE_INCLUDE_FILE trace-events-sample |
| 18 | * |
| 19 | * As we do an the bottom of this file. |
| 20 | * |
| 21 | * Notice that TRACE_SYSTEM should be defined outside of #if |
| 22 | * protection, just like TRACE_INCLUDE_FILE. |
| 23 | */ |
| 24 | #undef TRACE_SYSTEM |
| 25 | #define TRACE_SYSTEM sep |
| 26 | |
| 27 | /* |
| 28 | * Notice that this file is not protected like a normal header. |
| 29 | * We also must allow for rereading of this file. The |
| 30 | * |
| 31 | * || defined(TRACE_HEADER_MULTI_READ) |
| 32 | * |
| 33 | * serves this purpose. |
| 34 | */ |
| 35 | #if !defined(_TRACE_SEP_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ) |
| 36 | #define _TRACE_SEP_EVENTS_H |
| 37 | |
| 38 | #ifdef SEP_PERF_DEBUG |
| 39 | #define SEP_TRACE_FUNC_IN() trace_sep_func_start(__func__, 0) |
| 40 | #define SEP_TRACE_FUNC_OUT(branch) trace_sep_func_end(__func__, branch) |
| 41 | #define SEP_TRACE_EVENT(branch) trace_sep_misc_event(__func__, branch) |
| 42 | #else |
| 43 | #define SEP_TRACE_FUNC_IN() |
| 44 | #define SEP_TRACE_FUNC_OUT(branch) |
| 45 | #define SEP_TRACE_EVENT(branch) |
| 46 | #endif |
| 47 | |
| 48 | |
| 49 | /* |
| 50 | * All trace headers should include tracepoint.h, until we finally |
| 51 | * make it into a standard header. |
| 52 | */ |
| 53 | #include <linux/tracepoint.h> |
| 54 | |
| 55 | /* |
| 56 | * The TRACE_EVENT macro is broken up into 5 parts. |
| 57 | * |
| 58 | * name: name of the trace point. This is also how to enable the tracepoint. |
| 59 | * A function called trace_foo_bar() will be created. |
| 60 | * |
| 61 | * proto: the prototype of the function trace_foo_bar() |
| 62 | * Here it is trace_foo_bar(char *foo, int bar). |
| 63 | * |
| 64 | * args: must match the arguments in the prototype. |
| 65 | * Here it is simply "foo, bar". |
| 66 | * |
| 67 | * struct: This defines the way the data will be stored in the ring buffer. |
| 68 | * There are currently two types of elements. __field and __array. |
| 69 | * a __field is broken up into (type, name). Where type can be any |
| 70 | * type but an array. |
| 71 | * For an array. there are three fields. (type, name, size). The |
| 72 | * type of elements in the array, the name of the field and the size |
| 73 | * of the array. |
| 74 | * |
| 75 | * __array( char, foo, 10) is the same as saying char foo[10]. |
| 76 | * |
| 77 | * fast_assign: This is a C like function that is used to store the items |
| 78 | * into the ring buffer. |
| 79 | * |
| 80 | * printk: This is a way to print out the data in pretty print. This is |
| 81 | * useful if the system crashes and you are logging via a serial line, |
| 82 | * the data can be printed to the console using this "printk" method. |
| 83 | * |
| 84 | * Note, that for both the assign and the printk, __entry is the handler |
| 85 | * to the data structure in the ring buffer, and is defined by the |
| 86 | * TP_STRUCT__entry. |
| 87 | */ |
| 88 | TRACE_EVENT(sep_func_start, |
| 89 | |
| 90 | TP_PROTO(const char *name, int branch), |
| 91 | |
| 92 | TP_ARGS(name, branch), |
| 93 | |
| 94 | TP_STRUCT__entry( |
| 95 | __array(char, name, 20) |
| 96 | __field(int, branch) |
| 97 | ), |
| 98 | |
| 99 | TP_fast_assign( |
| 100 | strncpy(__entry->name, name, 20); |
| 101 | __entry->branch = branch; |
| 102 | ), |
| 103 | |
| 104 | TP_printk("func_start %s %d", __entry->name, __entry->branch) |
| 105 | ); |
| 106 | |
| 107 | TRACE_EVENT(sep_func_end, |
| 108 | |
| 109 | TP_PROTO(const char *name, int branch), |
| 110 | |
| 111 | TP_ARGS(name, branch), |
| 112 | |
| 113 | TP_STRUCT__entry( |
| 114 | __array(char, name, 20) |
| 115 | __field(int, branch) |
| 116 | ), |
| 117 | |
| 118 | TP_fast_assign( |
| 119 | strncpy(__entry->name, name, 20); |
| 120 | __entry->branch = branch; |
| 121 | ), |
| 122 | |
| 123 | TP_printk("func_end %s %d", __entry->name, __entry->branch) |
| 124 | ); |
| 125 | |
| 126 | TRACE_EVENT(sep_misc_event, |
| 127 | |
| 128 | TP_PROTO(const char *name, int branch), |
| 129 | |
| 130 | TP_ARGS(name, branch), |
| 131 | |
| 132 | TP_STRUCT__entry( |
| 133 | __array(char, name, 20) |
| 134 | __field(int, branch) |
| 135 | ), |
| 136 | |
| 137 | TP_fast_assign( |
| 138 | strncpy(__entry->name, name, 20); |
| 139 | __entry->branch = branch; |
| 140 | ), |
| 141 | |
| 142 | TP_printk("misc_event %s %d", __entry->name, __entry->branch) |
| 143 | ); |
| 144 | |
| 145 | |
| 146 | #endif |
| 147 | |
| 148 | /***** NOTICE! The #if protection ends here. *****/ |
| 149 | |
| 150 | |
| 151 | /* |
| 152 | * There are several ways I could have done this. If I left out the |
| 153 | * TRACE_INCLUDE_PATH, then it would default to the kernel source |
| 154 | * include/trace/events directory. |
| 155 | * |
| 156 | * I could specify a path from the define_trace.h file back to this |
| 157 | * file. |
| 158 | * |
| 159 | * #define TRACE_INCLUDE_PATH ../../samples/trace_events |
| 160 | * |
| 161 | * But the safest and easiest way to simply make it use the directory |
| 162 | * that the file is in is to add in the Makefile: |
| 163 | * |
| 164 | * CFLAGS_trace-events-sample.o := -I$(src) |
| 165 | * |
| 166 | * This will make sure the current path is part of the include |
| 167 | * structure for our file so that define_trace.h can find it. |
| 168 | * |
| 169 | * I could have made only the top level directory the include: |
| 170 | * |
| 171 | * CFLAGS_trace-events-sample.o := -I$(PWD) |
| 172 | * |
| 173 | * And then let the path to this directory be the TRACE_INCLUDE_PATH: |
| 174 | * |
| 175 | * #define TRACE_INCLUDE_PATH samples/trace_events |
| 176 | * |
| 177 | * But then if something defines "samples" or "trace_events" as a macro |
| 178 | * then we could risk that being converted too, and give us an unexpected |
| 179 | * result. |
| 180 | */ |
| 181 | #undef TRACE_INCLUDE_PATH |
| 182 | #undef TRACE_INCLUDE_FILE |
| 183 | #define TRACE_INCLUDE_PATH . |
| 184 | /* |
| 185 | * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal |
| 186 | */ |
| 187 | #define TRACE_INCLUDE_FILE sep_trace_events |
| 188 | #include <trace/define_trace.h> |