perf_counter: Add tracepoint support to perf list, perf stat

Add support to 'perf list' and 'perf stat' for kernel tracepoints. The
implementation creates a 'for_each_subsystem' and 'for_each_event' for
easy iteration over the tracepoints.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <426129bf9fcc8ee63bb094cf736e7316a7dcd77a.1248190728.git.jbaron@redhat.com>

2 files changed, 176 insertions, 1 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index d18c98edd00d..5a3cd3a34af1 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -12,6 +12,8 @@ int					nr_counters;
 
 struct perf_counter_attr                attrs[MAX_COUNTERS];
 
+static char default_debugfs_path[] = "/sys/kernel/debug/tracing/events";
+
 struct event_symbol {
         u8      type;
         u64     config;
@@ -110,6 +112,88 @@ static unsigned long hw_cache_stat[C(MAX)] = {
  [C(BPU)]       = (CACHE_READ),
 };
 
+#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st)            \
+        while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next)        \
+        if (snprintf(file, MAXPATHLEN, "%s/%s", default_debugfs_path,          \
+                        sys_dirent.d_name) &&                                  \
+           (!stat(file, &st)) && (S_ISDIR(st.st_mode)) &&                      \
+           (strcmp(sys_dirent.d_name, ".")) &&                                 \
+           (strcmp(sys_dirent.d_name, "..")))
+
+#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next, file, st)    \
+        while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next)        \
+        if (snprintf(file, MAXPATHLEN, "%s/%s/%s", default_debugfs_path,       \
+                        sys_dirent.d_name, evt_dirent.d_name) &&               \
+           (!stat(file, &st)) && (S_ISDIR(st.st_mode)) &&                      \
+           (strcmp(evt_dirent.d_name, ".")) &&                                 \
+           (strcmp(evt_dirent.d_name, "..")))
+
+#define MAX_EVENT_LENGTH 30
+
+static int valid_debugfs_mount(void)
+{
+        struct statfs st_fs;
+
+        if (statfs(default_debugfs_path, &st_fs) < 0)
+                return -ENOENT;
+        else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
+                return -ENOENT;
+        return 0;
+}
+
+static char *tracepoint_id_to_name(u64 config)
+{
+        static char tracepoint_name[2 * MAX_EVENT_LENGTH];
+        DIR *sys_dir, *evt_dir;
+        struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
+        struct stat st;
+        char id_buf[4];
+        int fd;
+        u64 id;
+        char evt_path[MAXPATHLEN];
+
+        if (valid_debugfs_mount())
+                return "unkown";
+
+        sys_dir = opendir(default_debugfs_path);
+        if (!sys_dir)
+                goto cleanup;
+
+        for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
+                evt_dir = opendir(evt_path);
+                if (!evt_dir)
+                        goto cleanup;
+                for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,
+                                                                evt_path, st) {
+                        snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id",
+                                 default_debugfs_path, sys_dirent.d_name,
+                                 evt_dirent.d_name);
+                        fd = open(evt_path, O_RDONLY);
+                        if (fd < 0)
+                                continue;
+                        if (read(fd, id_buf, sizeof(id_buf)) < 0) {
+                                close(fd);
+                                continue;
+                        }
+                        close(fd);
+                        id = atoll(id_buf);
+                        if (id == config) {
+                                closedir(evt_dir);
+                                closedir(sys_dir);
+                                snprintf(tracepoint_name, 2 * MAX_EVENT_LENGTH,
+                                        "%s:%s", sys_dirent.d_name,
+                                        evt_dirent.d_name);
+                                return tracepoint_name;
+                        }
+                }
+                closedir(evt_dir);
+        }
+
+cleanup:
+        closedir(sys_dir);
+        return "unkown";
+}
+
 static int is_cache_op_valid(u8 cache_type, u8 cache_op)
 {
         if (hw_cache_stat[cache_type] & COP(cache_op))
@@ -177,6 +261,9 @@ char *event_name(int counter)
                         return sw_event_names[config];
                 return "unknown-software";
 
+        case PERF_TYPE_TRACEPOINT:
+                return tracepoint_id_to_name(config);
+
         default:
                 break;
         }
@@ -265,6 +352,53 @@ parse_generic_hw_event(const char **str, struct perf_counter_attr *attr)
         return 1;
 }
 
+static int parse_tracepoint_event(const char **strp,
+                                    struct perf_counter_attr *attr)
+{
+        const char *evt_name;
+        char sys_name[MAX_EVENT_LENGTH];
+        char id_buf[4];
+        int fd;
+        unsigned int sys_length, evt_length;
+        u64 id;
+        char evt_path[MAXPATHLEN];
+
+        if (valid_debugfs_mount())
+                return 0;
+
+        evt_name = strchr(*strp, ':');
+        if (!evt_name)
+                return 0;
+
+        sys_length = evt_name - *strp;
+        if (sys_length >= MAX_EVENT_LENGTH)
+                return 0;
+
+        strncpy(sys_name, *strp, sys_length);
+        sys_name[sys_length] = '\0';
+        evt_name = evt_name + 1;
+        evt_length = strlen(evt_name);
+        if (evt_length >= MAX_EVENT_LENGTH)
+                return 0;
+
+        snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", default_debugfs_path,
+                                sys_name, evt_name);
+        fd = open(evt_path, O_RDONLY);
+        if (fd < 0)
+                return 0;
+
+        if (read(fd, id_buf, sizeof(id_buf)) < 0) {
+                close(fd);
+                return 0;
+        }
+        close(fd);
+        id = atoll(id_buf);
+        attr->config = id;
+        attr->type = PERF_TYPE_TRACEPOINT;
+        *strp = evt_name + evt_length;
+        return 1;
+}
+
 static int check_events(const char *str, unsigned int i)
 {
         int n;
@@ -374,7 +508,8 @@ parse_event_modifier(const char **strp, struct perf_counter_attr *attr)
  */
 static int parse_event_symbols(const char **str, struct perf_counter_attr *attr)
 {
-        if (!(parse_raw_event(str, attr) ||
+        if (!(parse_tracepoint_event(str, attr) ||
+              parse_raw_event(str, attr) ||
               parse_numeric_event(str, attr) ||
               parse_symbolic_event(str, attr) ||
               parse_generic_hw_event(str, attr)))
@@ -423,6 +558,42 @@ static const char * const event_type_descriptors[] = {
 };
 
 /*
+ * Print the events from <debugfs_mount_point>/tracing/events
+ */
+
+static void print_tracepoint_events(void)
+{
+        DIR *sys_dir, *evt_dir;
+        struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
+        struct stat st;
+        char evt_path[MAXPATHLEN];
+
+        if (valid_debugfs_mount())
+                return;
+
+        sys_dir = opendir(default_debugfs_path);
+        if (!sys_dir)
+                goto cleanup;
+
+        for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
+                evt_dir = opendir(evt_path);
+                if (!evt_dir)
+                        goto cleanup;
+                for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,
+                                                                evt_path, st) {
+                        snprintf(evt_path, MAXPATHLEN, "%s:%s",
+                                 sys_dirent.d_name, evt_dirent.d_name);
+                        fprintf(stderr, "  %-40s [%s]\n", evt_path,
+                                event_type_descriptors[PERF_TYPE_TRACEPOINT+1]);
+                }
+                closedir(evt_dir);
+        }
+
+cleanup:
+        closedir(sys_dir);
+}
+
+/*
  * Print the help text for the event symbols:
  */
 void print_events(void)
@@ -472,5 +643,7 @@ void print_events(void)
                 "rNNN");
         fprintf(stderr, "\n");
 
+        print_tracepoint_events();
+
         exit(129);
 }
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index b4be6071c105..68fe157d72fb 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -50,6 +50,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <sys/stat.h>
+#include <sys/statfs.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <stdlib.h>
@@ -80,6 +81,7 @@
 #include <netdb.h>
 #include <pwd.h>
 #include <inttypes.h>
+#include "../../../include/linux/magic.h"
 
 #ifndef NO_ICONV
 #include <iconv.h>