ftrace: event profile hooks
Impact: new tracing infrastructure feature
Provide infrastructure to generate software perf counter events
from tracepoints.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090319194233.557364871@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c3feea0..0e45c20 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -44,5 +44,6 @@
obj-$(CONFIG_EVENT_TRACER) += events.o
obj-$(CONFIG_EVENT_TRACER) += trace_export.o
obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
+obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o
libftrace-y := ftrace.o
diff --git a/kernel/trace/events.c b/kernel/trace/events.c
index 9fc918d..246f2aa 100644
--- a/kernel/trace/events.c
+++ b/kernel/trace/events.c
@@ -12,4 +12,3 @@
#include "trace_events_stage_2.h"
#include "trace_events_stage_3.h"
-#include <trace/trace_event_types.h>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 7c9a0cb..7cfb741 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -785,12 +785,23 @@
int id;
int (*raw_init)(void);
int (*show_format)(struct trace_seq *s);
+
+#ifdef CONFIG_EVENT_PROFILE
+ atomic_t profile_count;
+ int (*profile_enable)(struct ftrace_event_call *);
+ void (*profile_disable)(struct ftrace_event_call *);
+#endif
};
void event_trace_printk(unsigned long ip, const char *fmt, ...);
extern struct ftrace_event_call __start_ftrace_events[];
extern struct ftrace_event_call __stop_ftrace_events[];
+#define for_each_event(event) \
+ for (event = __start_ftrace_events; \
+ (unsigned long)event < (unsigned long)__stop_ftrace_events; \
+ event++)
+
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
new file mode 100644
index 0000000..22cba99
--- /dev/null
+++ b/kernel/trace/trace_event_profile.c
@@ -0,0 +1,31 @@
+/*
+ * trace event based perf counter profiling
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com>
+ *
+ */
+
+#include "trace.h"
+
+int ftrace_profile_enable(int event_id)
+{
+ struct ftrace_event_call *event;
+
+ for_each_event(event) {
+ if (event->id == event_id)
+ return event->profile_enable(event);
+ }
+
+ return -EINVAL;
+}
+
+void ftrace_profile_disable(int event_id)
+{
+ struct ftrace_event_call *event;
+
+ for_each_event(event) {
+ if (event->id == event_id)
+ return event->profile_disable(event);
+ }
+}
+
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7763db8..3047b56 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -19,11 +19,6 @@
static DEFINE_MUTEX(event_mutex);
-#define events_for_each(event) \
- for (event = __start_ftrace_events; \
- (unsigned long)event < (unsigned long)__stop_ftrace_events; \
- event++)
-
static void ftrace_clear_events(void)
{
struct ftrace_event_call *call = (void *)__start_ftrace_events;
@@ -90,7 +85,7 @@
}
mutex_lock(&event_mutex);
- events_for_each(call) {
+ for_each_event(call) {
if (!call->name || !call->regfunc)
continue;
@@ -628,7 +623,7 @@
if (!d_events)
return 0;
- events_for_each(call) {
+ for_each_event(call) {
/* The linker may leave blanks */
if (!call->name)
continue;
diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h
index 4c26d97..6b3261c 100644
--- a/kernel/trace/trace_events_stage_3.h
+++ b/kernel/trace/trace_events_stage_3.h
@@ -109,6 +109,40 @@
#undef TP_FMT
#define TP_FMT(fmt, args...) fmt "\n", ##args
+#ifdef CONFIG_EVENT_PROFILE
+#define _TRACE_PROFILE(call, proto, args) \
+static void ftrace_profile_##call(proto) \
+{ \
+ extern void perf_tpcounter_event(int); \
+ perf_tpcounter_event(event_##call.id); \
+} \
+ \
+static int ftrace_profile_enable_##call(struct ftrace_event_call *call) \
+{ \
+ int ret = 0; \
+ \
+ if (!atomic_inc_return(&call->profile_count)) \
+ ret = register_trace_##call(ftrace_profile_##call); \
+ \
+ return ret; \
+} \
+ \
+static void ftrace_profile_disable_##call(struct ftrace_event_call *call) \
+{ \
+ if (atomic_add_negative(-1, &call->profile_count)) \
+ unregister_trace_##call(ftrace_profile_##call); \
+}
+
+#define _TRACE_PROFILE_INIT(call) \
+ .profile_count = ATOMIC_INIT(-1), \
+ .profile_enable = ftrace_profile_enable_##call, \
+ .profile_disable = ftrace_profile_disable_##call,
+
+#else
+#define _TRACE_PROFILE(call, proto, args)
+#define _TRACE_PROFILE_INIT(call)
+#endif
+
#define _TRACE_FORMAT(call, proto, args, fmt) \
static void ftrace_event_##call(proto) \
{ \
@@ -147,6 +181,7 @@
#undef TRACE_FORMAT
#define TRACE_FORMAT(call, proto, args, fmt) \
_TRACE_FORMAT(call, PARAMS(proto), PARAMS(args), PARAMS(fmt)) \
+_TRACE_PROFILE(call, PARAMS(proto), PARAMS(args)) \
static struct ftrace_event_call __used \
__attribute__((__aligned__(4))) \
__attribute__((section("_ftrace_events"))) event_##call = { \
@@ -155,6 +190,7 @@
.raw_init = ftrace_init_event_##call, \
.regfunc = ftrace_reg_event_##call, \
.unregfunc = ftrace_unreg_event_##call, \
+ _TRACE_PROFILE_INIT(call) \
}
#undef __entry
@@ -162,6 +198,7 @@
#undef TRACE_EVENT
#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
+_TRACE_PROFILE(call, PARAMS(proto), PARAMS(args)) \
\
static struct ftrace_event_call event_##call; \
\
@@ -227,4 +264,11 @@
.regfunc = ftrace_raw_reg_event_##call, \
.unregfunc = ftrace_raw_unreg_event_##call, \
.show_format = ftrace_format_##call, \
+ _TRACE_PROFILE_INIT(call) \
}
+
+#include <trace/trace_event_types.h>
+
+#undef _TRACE_PROFILE
+#undef _TRACE_PROFILE_INIT
+
