perf tools: Save some loops using perf_evlist__id2evsel

Since we already ask for PERF_SAMPLE_ID and use it to quickly find the
associated evsel, add handler func + data to struct perf_evsel to avoid
using chains of if(strcmp(event_name)) and also to avoid all the linear
list searches via trace_event_find.

To demonstrate the technique convert 'perf sched' to it:

 # perf sched record sleep 5m

And then:

 Performance counter stats for '/tmp/oldperf sched lat':

        646.929438 task-clock                #    0.999 CPUs utilized
                 9 context-switches          #    0.000 M/sec
                 0 CPU-migrations            #    0.000 M/sec
            20,901 page-faults               #    0.032 M/sec
     1,290,144,450 cycles                    #    1.994 GHz
   <not supported> stalled-cycles-frontend
   <not supported> stalled-cycles-backend
     1,606,158,439 instructions              #    1.24  insns per cycle
       339,088,395 branches                  #  524.151 M/sec
         4,550,735 branch-misses             #    1.34% of all branches

       0.647524759 seconds time elapsed

Versus:

 Performance counter stats for 'perf sched lat':

        473.564691 task-clock                #    0.999 CPUs utilized
                 9 context-switches          #    0.000 M/sec
                 0 CPU-migrations            #    0.000 M/sec
            20,903 page-faults               #    0.044 M/sec
       944,367,984 cycles                    #    1.994 GHz
   <not supported> stalled-cycles-frontend
   <not supported> stalled-cycles-backend
     1,442,385,571 instructions              #    1.53  insns per cycle
       308,383,106 branches                  #  651.195 M/sec
         4,481,784 branch-misses             #    1.45% of all branches

       0.474215751 seconds time elapsed

[root@emilia ~]#

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-1kbzpl74lwi6lavpqke2u2p3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 62 insertions, 0 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index d44e3df13a8..b36f26fe767 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -207,6 +207,48 @@ out_free_attrs:
 	return err;
 }
 
+static struct perf_evsel *
+	perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
+{
+	struct perf_evsel *evsel;
+
+	list_for_each_entry(evsel, &evlist->entries, node) {
+		if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
+		    (int)evsel->attr.config == id)
+			return evsel;
+	}
+
+	return NULL;
+}
+
+int perf_evlist__set_tracepoints_handlers(struct perf_evlist *evlist,
+					  const struct perf_evsel_str_handler *assocs,
+					  size_t nr_assocs)
+{
+	struct perf_evsel *evsel;
+	int err;
+	size_t i;
+
+	for (i = 0; i < nr_assocs; i++) {
+		err = trace_event__id(assocs[i].name);
+		if (err < 0)
+			goto out;
+
+		evsel = perf_evlist__find_tracepoint_by_id(evlist, err);
+		if (evsel == NULL)
+			continue;
+
+		err = -EEXIST;
+		if (evsel->handler.func != NULL)
+			goto out;
+		evsel->handler.func = assocs[i].handler;
+	}
+
+	err = 0;
+out:
+	return err;
+}
+
 void perf_evlist__disable(struct perf_evlist *evlist)
 {
 	int cpu, thread;
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 2202e7b0410..f94ed7e0d98 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -36,6 +36,11 @@ struct perf_evlist {
 	struct perf_evsel *selected;
 };
 
+struct perf_evsel_str_handler {
+	const char *name;
+	void	   *handler;
+};
+
 struct perf_evsel;
 
 struct perf_evlist *perf_evlist__new(struct cpu_map *cpus,
@@ -51,6 +56,9 @@ int perf_evlist__add_attrs(struct perf_evlist *evlist,
 			   struct perf_event_attr *attrs, size_t nr_attrs);
 int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
 				 const char *tracepoints[], size_t nr_tracepoints);
+int perf_evlist__set_tracepoints_handlers(struct perf_evlist *evlist,
+					  const struct perf_evsel_str_handler *assocs,
+					  size_t nr_assocs);
 
 #define perf_evlist__add_attrs_array(evlist, array) \
 	perf_evlist__add_attrs(evlist, array, ARRAY_SIZE(array))
@@ -58,6 +66,9 @@ int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
 #define perf_evlist__add_tracepoints_array(evlist, array) \
 	perf_evlist__add_tracepoints(evlist, array, ARRAY_SIZE(array))
 
+#define perf_evlist__set_tracepoints_handlers_array(evlist, array) \
+	perf_evlist__set_tracepoints_handlers(evlist, array, ARRAY_SIZE(array))
+
 void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
 			 int cpu, int thread, u64 id);
 
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 6421c07f501..326b8e4d503 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -61,6 +61,10 @@ struct perf_evsel {
 		off_t		id_offset;
 	};
 	struct cgroup_sel	*cgrp;
+	struct {
+		void		*func;
+		void		*data;
+	} handler;
 	bool 			supported;
 };
 
diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
index 89ff1b551a7..b0e1aadba8d 100644
--- a/tools/perf/util/tool.h
+++ b/tools/perf/util/tool.h
@@ -1,8 +1,13 @@
 #ifndef __PERF_TOOL_H
 #define __PERF_TOOL_H
 
+#include <stdbool.h>
+
 struct perf_session;
+union perf_event;
+struct perf_evlist;
 struct perf_evsel;
+struct perf_sample;
 struct perf_tool;
 struct machine;