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Commit 4f41c013 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf/ftrace: Optimize perf/tracepoint interaction for single events 



When we've got but a single event per tracepoint
there is no reason to try and multiplex it so don't.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ef4f30f5

include/linux/ftrace_event.h

+5 −3
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ struct ftrace_event_call { 
	void			*data;



	int			perf_refcount;

	void			*perf_data;

	int			(*perf_event_enable)(struct ftrace_event_call *);

	void			(*perf_event_disable)(struct ftrace_event_call *);

};
@@ -190,7 +191,7 @@ struct perf_event; 


DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);



extern int perf_trace_enable(int event_id);

extern int perf_trace_enable(int event_id, void *data);

extern void perf_trace_disable(int event_id);

extern int ftrace_profile_set_filter(struct perf_event *event, int event_id,

				     char *filter_str);
@@ -201,11 +202,12 @@ perf_trace_buf_prepare(int size, unsigned short type, int *rctxp, 


static inline void

perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,

		       u64 count, unsigned long irq_flags, struct pt_regs *regs)

		       u64 count, unsigned long irq_flags, struct pt_regs *regs,

		       void *event)

{

	struct trace_entry *entry = raw_data;



	perf_tp_event(entry->type, addr, count, raw_data, size, regs);

	perf_tp_event(entry->type, addr, count, raw_data, size, regs, event);

	perf_swevent_put_recursion_context(rctx);

	local_irq_restore(irq_flags);

}

include/linux/perf_event.h

+1 −1
Original line number Diff line number Diff line
@@ -994,7 +994,7 @@ static inline bool perf_paranoid_kernel(void) 


extern void perf_event_init(void);

extern void perf_tp_event(int event_id, u64 addr, u64 count, void *record,

			  int entry_size, struct pt_regs *regs);

			  int entry_size, struct pt_regs *regs, void *event);

extern void perf_bp_event(struct perf_event *event, void *data);



#ifndef perf_misc_flags

include/trace/ftrace.h

+2 −1
Original line number Diff line number Diff line
@@ -785,7 +785,8 @@ perf_trace_templ_##call(struct ftrace_event_call *event_call, \ 
	{ assign; }							\

									\

	perf_trace_buf_submit(entry, __entry_size, rctx, __addr,	\

			       __count, irq_flags, __regs);		\

			       __count, irq_flags, __regs, 		\

			      event_call->perf_data);			\

}



#undef DEFINE_EVENT

kernel/perf_event.c

+10 −5
Original line number Diff line number Diff line
@@ -4468,8 +4468,9 @@ static int swevent_hlist_get(struct perf_event *event) 
#ifdef CONFIG_EVENT_TRACING



void perf_tp_event(int event_id, u64 addr, u64 count, void *record,

		   int entry_size, struct pt_regs *regs)

		   int entry_size, struct pt_regs *regs, void *event)

{

	const int type = PERF_TYPE_TRACEPOINT;

	struct perf_sample_data data;

	struct perf_raw_record raw = {

		.size = entry_size,
@@ -4479,9 +4480,13 @@ void perf_tp_event(int event_id, u64 addr, u64 count, void *record, 
	perf_sample_data_init(&data, addr);

	data.raw = &raw;



	/* Trace events already protected against recursion */

	do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,

			 &data, regs);

	if (!event) {

		do_perf_sw_event(type, event_id, count, 1, &data, regs);

		return;

	}



	if (perf_swevent_match(event, type, event_id, &data, regs))

		perf_swevent_add(event, count, 1, &data, regs);

}

EXPORT_SYMBOL_GPL(perf_tp_event);
@@ -4514,7 +4519,7 @@ static const struct pmu *tp_perf_event_init(struct perf_event *event) 
			!capable(CAP_SYS_ADMIN))

		return ERR_PTR(-EPERM);



	if (perf_trace_enable(event->attr.config))

	if (perf_trace_enable(event->attr.config, event))

		return NULL;



	event->destroy = tp_perf_event_destroy;

kernel/trace/trace_event_perf.c

+7 −4
Original line number Diff line number Diff line
@@ -27,13 +27,15 @@ typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)]) 
/* Count the events in use (per event id, not per instance) */

static int	total_ref_count;



static int perf_trace_event_enable(struct ftrace_event_call *event)

static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)

{

	char *buf;

	int ret = -ENOMEM;



	if (event->perf_refcount++ > 0)

	if (event->perf_refcount++ > 0) {

		event->perf_data = NULL;

		return 0;

	}



	if (!total_ref_count) {

		buf = (char *)alloc_percpu(perf_trace_t);
@@ -51,6 +53,7 @@ static int perf_trace_event_enable(struct ftrace_event_call *event) 


	ret = event->perf_event_enable(event);

	if (!ret) {

		event->perf_data = data;

		total_ref_count++;

		return 0;

	}
@@ -68,7 +71,7 @@ static int perf_trace_event_enable(struct ftrace_event_call *event) 
	return ret;

}



int perf_trace_enable(int event_id)

int perf_trace_enable(int event_id, void *data)

{

	struct ftrace_event_call *event;

	int ret = -EINVAL;
@@ -77,7 +80,7 @@ int perf_trace_enable(int event_id) 
	list_for_each_entry(event, &ftrace_events, list) {

		if (event->id == event_id && event->perf_event_enable &&

		    try_module_get(event->mod)) {

			ret = perf_trace_event_enable(event);

			ret = perf_trace_event_enable(event, data);

			break;

		}

	}