[PATCH 06/10] perf, tools: Automatically look for event file name for cpu

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

When no JSON event file is specified automatically look
for a suitable file in ~/.cache/pmu-events.

The event file format is per architecture, but can be
extended for other architectures.

v2: Supports XDG_CACHE_HOME and defaults to ~/.cache/pmu-events
v3: Minor updates and handle EVENTMAP.
v4: Unify with header.c. Now uses CPUID directly.
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 tools/perf/arch/x86/util/header.c | 19 ++++++++++++++++---
 tools/perf/util/jevents.c         | 40 +++++++++++++++++++++++++++++++++++++++
 tools/perf/util/jevents.h         |  1 +
 tools/perf/util/pmu.c             |  2 +-
 4 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
index 146d12a..76e0ece 100644
--- a/tools/perf/arch/x86/util/header.c
+++ b/tools/perf/arch/x86/util/header.c
@@ -5,6 +5,7 @@
 #include <string.h>
 
 #include "../../util/header.h"
+#include "../../util/jevents.h"
 
 static inline void
 cpuid(unsigned int op, unsigned int *a, unsigned int *b, unsigned int *c,
@@ -19,8 +20,8 @@ cpuid(unsigned int op, unsigned int *a, unsigned int *b, unsigned int *c,
 			: "a" (op));
 }
 
-int
-get_cpuid(char *buffer, size_t sz)
+static int
+__get_cpuid(char *buffer, size_t sz, const char *fmt)
 {
 	unsigned int a, b, c, d, lvl;
 	int family = -1, model = -1, step = -1;
@@ -48,7 +49,7 @@ get_cpuid(char *buffer, size_t sz)
 		if (family >= 0x6)
 			model += ((a >> 16) & 0xf) << 4;
 	}
-	nb = scnprintf(buffer, sz, "%s,%u,%u,%u$", vendor, family, model, step);
+	nb = scnprintf(buffer, sz, fmt, vendor, family, model, step);
 
 	/* look for end marker to ensure the entire data fit */
 	if (strchr(buffer, '$')) {
@@ -57,3 +58,15 @@ get_cpuid(char *buffer, size_t sz)
 	}
 	return -1;
 }
+
+int get_cpuid(char *buffer, size_t sz)
+{
+	return __get_cpuid(buffer, sz, "%s,%u,%u,%u$");
+}
+
+char *get_cpu_str(void)
+{
+	char *buf = malloc(128);
+	__get_cpuid(buf, 128, "%s-%d-%X-core");
+	return buf;
+}
diff --git a/tools/perf/util/jevents.c b/tools/perf/util/jevents.c
index 023757c..ef4c047 100644
--- a/tools/perf/util/jevents.c
+++ b/tools/perf/util/jevents.c
@@ -39,6 +39,44 @@
 #include "json.h"
 #include "jevents.h"
 
+__attribute__((weak)) char *get_cpu_str(void)
+{
+	return NULL;
+}
+
+static const char *json_default_name(void)
+{
+	char *cache;
+	char *idstr = get_cpu_str();
+	char *res = NULL;
+	char *home = NULL;
+	char *emap;
+
+	emap = getenv("EVENTMAP");
+	if (emap) {
+		if (access(emap, R_OK) == 0)
+			return emap;
+		if (asprintf(&idstr, "%s-core", emap) < 0)
+			return NULL;
+	}
+
+	cache = getenv("XDG_CACHE_HOME");
+	if (!cache) {
+		home = getenv("HOME");
+		if (!home || asprintf(&cache, "%s/.cache", home) < 0)
+			goto out;
+	}
+	if (cache && idstr)
+		res = mkpath("%s/pmu-events/%s.json",
+			     cache,
+			     idstr);
+	if (home)
+		free(cache);
+out:
+	free(idstr);
+	return res;
+}
+
 static void addfield(char *map, char **dst, const char *sep,
 		     const char *a, jsmntok_t *bt)
 {
@@ -171,6 +209,8 @@ int json_events(const char *fn,
 	int i, j, len;
 	char *map;
 
+	if (!fn)
+		fn = json_default_name();
 	tokens = parse_json(fn, &map, &size, &len);
 	if (!tokens)
 		return -EIO;
diff --git a/tools/perf/util/jevents.h b/tools/perf/util/jevents.h
index fbc4549..86a94dd 100644
--- a/tools/perf/util/jevents.h
+++ b/tools/perf/util/jevents.h
@@ -4,5 +4,6 @@
 int json_events(const char *fn,
 		int (*func)(void *data, char *name, char *event, char *desc),
 		void *data);
+char *get_cpu_str(void);
 
 #endif
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 9f154af..fa21319 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -433,7 +433,7 @@ static struct perf_pmu *pmu_lookup(const char *name)
 	if (pmu_aliases(name, &aliases))
 		return NULL;
 
-	if (!strcmp(name, "cpu") && json_file)
+	if (!strcmp(name, "cpu"))
 		json_events(json_file, add_alias, &aliases);
 
 	if (pmu_type(name, &type))
-- 
1.9.3

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