diff options
Diffstat (limited to 'samples/trace_events/trace-events-sample.h')
-rw-r--r-- | samples/trace_events/trace-events-sample.h | 56 |
1 files changed, 32 insertions, 24 deletions
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 128a897..f24ae37 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -1,4 +1,30 @@ /* + * If TRACE_SYSTEM is defined, that will be the directory created + * in the ftrace directory under /debugfs/tracing/events/<system> + * + * The define_trace.h below will also look for a file name of + * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. + * In this case, it would look for sample.h + * + * If the header name will be different than the system name + * (as in this case), then you can override the header name that + * define_trace.h will look up by defining TRACE_INCLUDE_FILE + * + * This file is called trace-events-sample.h but we want the system + * to be called "sample". Therefore we must define the name of this + * file: + * + * #define TRACE_INCLUDE_FILE trace-events-sample + * + * As we do an the bottom of this file. + * + * Notice that TRACE_SYSTEM should be defined outside of #if + * protection, just like TRACE_INCLUDE_FILE. + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM sample + +/* * Notice that this file is not protected like a normal header. * We also must allow for rereading of this file. The * @@ -16,24 +42,6 @@ #include <linux/tracepoint.h> /* - * If TRACE_SYSTEM is defined, that will be the directory created - * in the ftrace directory under /debugfs/tracing/events/<system> - * - * The define_trace.h belowe will also look for a file name of - * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. - * - * If you want a different system than file name, you can override - * the header name by defining TRACE_INCLUDE_FILE - * - * If this file was called, goofy.h, then we would define: - * - * #define TRACE_INCLUDE_FILE goofy - * - */ -#undef TRACE_SYSTEM -#define TRACE_SYSTEM sample - -/* * The TRACE_EVENT macro is broken up into 5 parts. * * name: name of the trace point. This is also how to enable the tracepoint. @@ -99,13 +107,13 @@ TRACE_EVENT(foo_bar, * * #define TRACE_INCLUDE_PATH ../../samples/trace_events * - * But I chose to simply make it use the current directory and then in - * the Makefile I added: + * But the safest and easiest way to simply make it use the directory + * that the file is in is to add in the Makefile: * - * CFLAGS_trace-events-sample.o := -I$(PWD)/samples/trace_events/ + * CFLAGS_trace-events-sample.o := -I$(src) * * This will make sure the current path is part of the include - * structure for our file so that we can find it. + * structure for our file so that define_trace.h can find it. * * I could have made only the top level directory the include: * @@ -115,8 +123,8 @@ TRACE_EVENT(foo_bar, * * #define TRACE_INCLUDE_PATH samples/trace_events * - * But then if something defines "samples" or "trace_events" then we - * could risk that being converted too, and give us an unexpected + * But then if something defines "samples" or "trace_events" as a macro + * then we could risk that being converted too, and give us an unexpected * result. */ #undef TRACE_INCLUDE_PATH |