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SubjectRe: [PATCH 5/7] ftrace, perf: Add support to use function tracepoint in perf
On Thu, Feb 02, 2012 at 07:14:12PM +0100, Frederic Weisbecker wrote:
> On Sat, Jan 28, 2012 at 07:43:27PM +0100, Jiri Olsa wrote:
> > Adding perf registration support for the ftrace function event,
> > so it is now possible to register it via perf interface.
> >
> > The perf_event struct statically contains ftrace_ops as a handle
> > for function tracer. The function tracer is registered/unregistered
> > in open/close actions.
> >
> > To be efficient, we enable/disable ftrace_ops each time the traced

SNIP

> > +
> > + return -EINVAL;
> > +}
>
> All the above from perf_ftrace_function_call() to here should perhaps
> go to trace_function.c.

hm, I'd call it rather trace_perf_function.c

>
> > diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
> > index bbeec31..867653c 100644
> > --- a/kernel/trace/trace_export.c
> > +++ b/kernel/trace/trace_export.c
> > @@ -131,6 +131,28 @@ ftrace_define_fields_##name(struct ftrace_event_call *event_call) \
> >
> > #include "trace_entries.h"
> >
> > +static int ftrace_event_class_register(struct ftrace_event_call *call,
> > + enum trace_reg type, void *data)
> > +{
> > + switch (type) {
> > + case TRACE_REG_PERF_REGISTER:
> > + case TRACE_REG_PERF_UNREGISTER:
> > + return 0;
> > + case TRACE_REG_PERF_OPEN:
> > + case TRACE_REG_PERF_CLOSE:
> > + case TRACE_REG_PERF_ADD:
> > + case TRACE_REG_PERF_DEL:
> > +#ifdef CONFIG_PERF_EVENTS
> > + return perf_ftrace_event_register(call, type, data);
> > +#endif
> > + case TRACE_REG_REGISTER:
> > + case TRACE_REG_UNREGISTER:
> > + break;
> > + }
> > +
> > + return -EINVAL;
> > +}
>
> Hmm, one day we'll need to demux here. What about adding an argument to
> FTRACE_ENTRY() to add the pointer to .reg ?

ok, would something like the attached change be ok?

thanks,
jirka


---
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 55c6ea0..638476a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -68,6 +68,10 @@ enum trace_type {
#undef FTRACE_ENTRY_DUP
#define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)

+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, regfn) \
+ FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
#include "trace_entries.h"

/*
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index bbeec31..f74de86 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -18,6 +18,14 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM ftrace

+/*
+ * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
+ * function and thus become accesible via perf.
+ */
+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, regfn) \
+ FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
/* not needed for this file */
#undef __field_struct
#define __field_struct(type, item)
@@ -152,13 +160,14 @@ ftrace_define_fields_##name(struct ftrace_event_call *event_call) \
#undef F_printk
#define F_printk(fmt, args...) #fmt ", " __stringify(args)

-#undef FTRACE_ENTRY
-#define FTRACE_ENTRY(call, struct_name, etype, tstruct, print) \
+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, regfn)\
\
struct ftrace_event_class event_class_ftrace_##call = { \
.system = __stringify(TRACE_SYSTEM), \
.define_fields = ftrace_define_fields_##call, \
.fields = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
+ .reg = regfn, \
}; \
\
struct ftrace_event_call __used event_##call = { \
@@ -170,4 +179,9 @@ struct ftrace_event_call __used event_##call = { \
struct ftrace_event_call __used \
__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;

+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(call, struct_name, etype, tstruct, print) \
+ FTRACE_ENTRY_REG(call, struct_name, etype, \
+ PARAMS(tstruct), PARAMS(print), NULL)
+
#include "trace_entries.h"

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