perf tools: Reconstruct event with modifiers from perf_event_attr

The modifiers:

  k		kernel space
  u		user space
  h		hypervisor
  G		guest
  H		host
  p, pp, ppp    precision level (PEBS)

that can be suffixed to an event were lost when tools used event_name()
to reconstruct them from the perf_event_attr entries in a perf.data
file.

Fix it by following the defaults used for these modifiers in the current
codebase, so:

 $ perf record -e instructions:u usleep 1 2> /dev/null
 $ perf evlist
 instructions:u
 $ perf record -e cycles:k usleep 1 2> /dev/null
 $ perf evlist
 cycles:k
 $ perf record -e cycles:kh usleep 1 2> /dev/null
 $ perf evlist
 cycles:kh
 $ perf record -e cache-misses:G usleep 1 2> /dev/null
 $ perf evlist
 cache-misses:G
 $ perf record -e cycles:ppk usleep 1 2> /dev/null
 $ perf evlist
 cycles:kpp
 $

Also works with 'top', 'report', etc.

More work needed to cover tracepoints and software events while not
dragging lots of baggage to the python binding, this is a minimal fix
for v3.5.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
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-4hl5glle0hxlklw4usva1mkt@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -15,6 +15,7 @@
 #include "cpumap.h"
 #include "thread_map.h"
 #include "target.h"
+#include "../../include/linux/perf_event.h"
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
 #define GROUP_FD(group_fd, cpu) (*(int *)xyarray__entry(group_fd, cpu, 0))
@@ -64,6 +65,95 @@ struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr, int idx)
 	return evsel;
 }
 
+static const char *perf_evsel__hw_names[PERF_COUNT_HW_MAX] = {
+	"cycles",
+	"instructions",
+	"cache-references",
+	"cache-misses",
+	"branches",
+	"branch-misses",
+	"bus-cycles",
+	"stalled-cycles-frontend",
+	"stalled-cycles-backend",
+	"ref-cycles",
+};
+
+const char *__perf_evsel__hw_name(u64 config)
+{
+	if (config < PERF_COUNT_HW_MAX && perf_evsel__hw_names[config])
+		return perf_evsel__hw_names[config];
+
+	return "unknown-hardware";
+}
+
+static int perf_evsel__hw_name(struct perf_evsel *evsel, char *bf, size_t size)
+{
+	int colon = 0;
+	struct perf_event_attr *attr = &evsel->attr;
+	int r = scnprintf(bf, size, "%s", __perf_evsel__hw_name(attr->config));
+	bool exclude_guest_default = false;
+
+#define MOD_PRINT(context, mod)	do {					\
+		if (!attr->exclude_##context) {				\
+			if (!colon) colon = r++;			\
+			r += scnprintf(bf + r, size - r, "%c", mod);	\
+		} } while(0)
+
+	if (attr->exclude_kernel || attr->exclude_user || attr->exclude_hv) {
+		MOD_PRINT(kernel, 'k');
+		MOD_PRINT(user, 'u');
+		MOD_PRINT(hv, 'h');
+		exclude_guest_default = true;
+	}
+
+	if (attr->precise_ip) {
+		if (!colon)
+			colon = r++;
+		r += scnprintf(bf + r, size - r, "%.*s", attr->precise_ip, "ppp");
+		exclude_guest_default = true;
+	}
+
+	if (attr->exclude_host || attr->exclude_guest == exclude_guest_default) {
+		MOD_PRINT(host, 'H');
+		MOD_PRINT(guest, 'G');
+	}
+#undef MOD_PRINT
+	if (colon)
+		bf[colon] = ':';
+	return r;
+}
+
+int perf_evsel__name(struct perf_evsel *evsel, char *bf, size_t size)
+{
+	int ret;
+
+	switch (evsel->attr.type) {
+	case PERF_TYPE_RAW:
+		ret = scnprintf(bf, size, "raw 0x%" PRIx64, evsel->attr.config);
+		break;
+
+	case PERF_TYPE_HARDWARE:
+		ret = perf_evsel__hw_name(evsel, bf, size);
+		break;
+	default:
+		/*
+		 * FIXME
+ 		 *
+		 * This is the minimal perf_evsel__name so that we can
+		 * reconstruct event names taking into account event modifiers.
+		 *
+		 * The old event_name uses it now for raw anr hw events, so that
+		 * we don't drag all the parsing stuff into the python binding.
+		 *
+		 * On the next devel cycle the rest of the event naming will be
+		 * brought here.
+ 		 */
+		return 0;
+	}
+
+	return ret;
+}
+
 void perf_evsel__config(struct perf_evsel *evsel, struct perf_record_opts *opts,
 			struct perf_evsel *first)
 {

tools/perf/util/evsel.h

@@ -83,6 +83,9 @@ void perf_evsel__config(struct perf_evsel *evsel,
 			struct perf_record_opts *opts,
 			struct perf_evsel *first);
 
+const char* __perf_evsel__hw_name(u64 config);
+int perf_evsel__name(struct perf_evsel *evsel, char *bf, size_t size);
+
 int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
 int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads);
 int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus);

tools/perf/util/parse-events.c

@@ -62,19 +62,6 @@ static struct event_symbol event_symbols[] = {
 #define PERF_EVENT_TYPE(config)		__PERF_EVENT_FIELD(config, TYPE)
 #define PERF_EVENT_ID(config)		__PERF_EVENT_FIELD(config, EVENT)
 
-static const char *hw_event_names[PERF_COUNT_HW_MAX] = {
-	"cycles",
-	"instructions",
-	"cache-references",
-	"cache-misses",
-	"branches",
-	"branch-misses",
-	"bus-cycles",
-	"stalled-cycles-frontend",
-	"stalled-cycles-backend",
-	"ref-cycles",
-};
-
 static const char *sw_event_names[PERF_COUNT_SW_MAX] = {
 	"cpu-clock",
 	"task-clock",
@@ -300,6 +287,16 @@ const char *event_name(struct perf_evsel *evsel)
 	u64 config = evsel->attr.config;
 	int type = evsel->attr.type;
 
+	if (type == PERF_TYPE_RAW || type == PERF_TYPE_HARDWARE) {
+		/*
+ 		 * XXX minimal fix, see comment on perf_evsen__name, this static buffer
+ 		 * will go away together with event_name in the next devel cycle.
+ 		 */
+		static char bf[128];
+		perf_evsel__name(evsel, bf, sizeof(bf));
+		return bf;
+	}
+
 	if (evsel->name)
 		return evsel->name;
 
@@ -317,9 +314,7 @@ const char *__event_name(int type, u64 config)
 
 	switch (type) {
 	case PERF_TYPE_HARDWARE:
-		if (config < PERF_COUNT_HW_MAX && hw_event_names[config])
+		return __perf_evsel__hw_name(config);
-			return hw_event_names[config];
-		return "unknown-hardware";
 
 	case PERF_TYPE_HW_CACHE: {
 		u8 cache_type, cache_op, cache_result;