Commit 12473965 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Steven Rostedt
Browse files

tracing/perf: Reimplement TP_perf_assign() logic 

The next patch tries to avoid the costly perf_trace_buf_* calls
when possible but there is a problem. We can only do this if
__task == NULL, perf_tp_event(task != NULL) has the additional
code for this case.

Unfortunately, TP_perf_assign/__perf_xxx which changes the default
values of __count/__task variables for perf_trace_buf_submit() is
called "too late", after we already did perf_trace_buf_prepare(),
and the optimization above can't work.

So this patch simply embeds __perf_xxx() into TP_ARGS(), this way
DECLARE_EVENT_CLASS() can use the result of assignments hidden in
"args" right after ftrace_get_offsets_##call() which is mostly
trivial. This allows us to have the fast-path "__task != NULL"
check at the start, see the next patch.

Link: http://lkml.kernel.org/r/20130806160844.GA2739@redhat.com



Tested-by: default avatarDavid Ahern <dsahern@gmail.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 36009d07

include/trace/events/sched.h

+3 −13
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_template, 


	TP_PROTO(struct task_struct *p, int success),



	TP_ARGS(p, success),

	TP_ARGS(__perf_task(p), success),



	TP_STRUCT__entry(

		__array(	char,	comm,	TASK_COMM_LEN	)
@@ -73,9 +73,6 @@ DECLARE_EVENT_CLASS(sched_wakeup_template, 
		__entry->prio		= p->prio;

		__entry->success	= success;

		__entry->target_cpu	= task_cpu(p);

	)

	TP_perf_assign(

		__perf_task(p);

	),



	TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d",
@@ -313,7 +310,7 @@ DECLARE_EVENT_CLASS(sched_stat_template, 


	TP_PROTO(struct task_struct *tsk, u64 delay),



	TP_ARGS(tsk, delay),

	TP_ARGS(__perf_task(tsk), __perf_count(delay)),



	TP_STRUCT__entry(

		__array( char,	comm,	TASK_COMM_LEN	)
@@ -325,10 +322,6 @@ DECLARE_EVENT_CLASS(sched_stat_template, 
		memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);

		__entry->pid	= tsk->pid;

		__entry->delay	= delay;

	)

	TP_perf_assign(

		__perf_count(delay);

		__perf_task(tsk);

	),



	TP_printk("comm=%s pid=%d delay=%Lu [ns]",
@@ -376,7 +369,7 @@ DECLARE_EVENT_CLASS(sched_stat_runtime, 


	TP_PROTO(struct task_struct *tsk, u64 runtime, u64 vruntime),



	TP_ARGS(tsk, runtime, vruntime),

	TP_ARGS(tsk, __perf_count(runtime), vruntime),



	TP_STRUCT__entry(

		__array( char,	comm,	TASK_COMM_LEN	)
@@ -390,9 +383,6 @@ DECLARE_EVENT_CLASS(sched_stat_runtime, 
		__entry->pid		= tsk->pid;

		__entry->runtime	= runtime;

		__entry->vruntime	= vruntime;

	)

	TP_perf_assign(

		__perf_count(runtime);

	),



	TP_printk("comm=%s pid=%d runtime=%Lu [ns] vruntime=%Lu [ns]",

include/trace/ftrace.h

+11 −8
Original line number Diff line number Diff line
@@ -507,8 +507,14 @@ static inline notrace int ftrace_get_offsets_##call( \ 
#undef TP_fast_assign

#define TP_fast_assign(args...) args



#undef TP_perf_assign

#define TP_perf_assign(args...)

#undef __perf_addr

#define __perf_addr(a)	(a)



#undef __perf_count

#define __perf_count(c)	(c)



#undef __perf_task

#define __perf_task(t)	(t)



#undef DECLARE_EVENT_CLASS

#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
@@ -636,16 +642,13 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call 
#define __get_str(field) (char *)__get_dynamic_array(field)



#undef __perf_addr

#define __perf_addr(a) __addr = (a)

#define __perf_addr(a)	(__addr = (a))



#undef __perf_count

#define __perf_count(c) __count = (c)

#define __perf_count(c)	(__count = (c))



#undef __perf_task

#define __perf_task(t) __task = (t)



#undef TP_perf_assign

#define TP_perf_assign(args...) args

#define __perf_task(t)	(__task = (t))



#undef DECLARE_EVENT_CLASS

#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\

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