[PATCHv2 1/2] perf tools: Collect tracing event data files directly

Jiri Olsa
2011-09-26T09:12:31Z

Changing the way the event files are searched by quering specified
event files directly, instead of walking the events directory.

Hopefully this way is more straightforward and faster.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
tools/perf/util/parse-events.h | 1 +
tools/perf/util/trace-event-info.c | 231 +++++++++++++++--------------------
2 files changed, 100 insertions(+), 132 deletions(-)

diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 2f8e375..1ea02ad 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -15,6 +15,7 @@ struct option;
struct tracepoint_path {
char *system;
char *name;
+ bool done;
struct tracepoint_path *next;
};

diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
index 3403f81..cf8f89e 100644
--- a/tools/perf/util/trace-event-info.c
+++ b/tools/perf/util/trace-event-info.c
@@ -238,136 +238,98 @@ static void read_header_files(void)
put_tracing_file(path);
}

-static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
+static char *get_format_file(char *sys, char *name)
{
- while (tps) {
- if (!strcmp(sys, tps->name))
- return true;
- tps = tps->next;
- }
-
- return false;
-}
-
-static void copy_event_system(const char *sys, struct tracepoint_path *tps)
-{
- struct dirent *dent;
- struct stat st;
- char *format;
- DIR *dir;
- int count = 0;
- int ret;
-
- dir = opendir(sys);
- if (!dir)
- die("can't read directory '%s'", sys);
-
- while ((dent = readdir(dir))) {
- if (dent->d_type != DT_DIR ||
- strcmp(dent->d_name, ".") == 0 ||
- strcmp(dent->d_name, "..") == 0 ||
- !name_in_tp_list(dent->d_name, tps))
- continue;
- format = malloc_or_die(strlen(sys) + strlen(dent->d_name) + 10);
- sprintf(format, "%s/%s/format", sys, dent->d_name);
- ret = stat(format, &st);
- free(format);
- if (ret < 0)
- continue;
- count++;
- }
-
- write_or_die(&count, 4);
+ char *file, *path;

- rewinddir(dir);
- while ((dent = readdir(dir))) {
- if (dent->d_type != DT_DIR ||
- strcmp(dent->d_name, ".") == 0 ||
- strcmp(dent->d_name, "..") == 0 ||
- !name_in_tp_list(dent->d_name, tps))
- continue;
- format = malloc_or_die(strlen(sys) + strlen(dent->d_name) + 10);
- sprintf(format, "%s/%s/format", sys, dent->d_name);
- ret = stat(format, &st);
+ path = get_tracing_file("events");
+ if (!path)
+ return NULL;

- if (ret >= 0)
- record_file(format, 8);
+ /*
+ * The '+ 5' is for '/' we add to the patch, plus NULL byte,
+ * and one safety byte ;)
+ */
+ file = malloc_or_die(strlen(path) + strlen(sys) +
+ strlen(name) + strlen("format") + 5);

- free(format);
- }
- closedir(dir);
+ sprintf(file, "%s/%s/%s/format", path, sys, name);
+ return file;
}

-static void read_ftrace_files(struct tracepoint_path *tps)
+static void put_format_file(char *file)
{
- char *path;
-
- path = get_tracing_file("events/ftrace");
-
- copy_event_system(path, tps);
-
- put_tracing_file(path);
+ free(file);
}

-static bool system_in_tp_list(char *sys, struct tracepoint_path *tps)
+/*
+ * Walk tracepoint event objects and store them.
+ * Only those matching the sys parameter are stored
+ * and marked as done.
+ */
+static void read_event_files_system(struct tracepoint_path *tps,
+ const char *sys)
{
+ off_t count_pos;
+ u32 count = 0;
+
+ /* Place for number of events under single system. */
+ count_pos = lseek(output_fd, 0, SEEK_CUR);
+ write_or_die(&count, 4);
+
while (tps) {
- if (!strcmp(sys, tps->system))
- return true;
+ if ((!tps->done) &&
+ (!strcmp(sys, tps->system))) {
+ char *file;
+
+ file = get_format_file(tps->system, tps->name);
+ if (file) {
+ record_file(file, 8);
+ count++;
+ }
+
+ put_format_file(file);
+ tps->done = 1;
+ }
+
tps = tps->next;
}

- return false;
+ if (pwrite(output_fd, &count, 4, count_pos) < 0)
+ die("pwrite");
}

+/*
+ * We have all needed tracepoint event files stored in
+ * the tracepoint_path objects.
+ *
+ * - first we store ftrace system events
+ * - then we walk all '!done' event objects
+ * and process them
+ */
static void read_event_files(struct tracepoint_path *tps)
{
- struct dirent *dent;
- struct stat st;
- char *path;
- char *sys;
- DIR *dir;
- int count = 0;
- int ret;
-
- path = get_tracing_file("events");
+ off_t count_pos;
+ u32 count = 0;

- dir = opendir(path);
- if (!dir)
- die("can't read directory '%s'", path);
-
- while ((dent = readdir(dir))) {
- if (dent->d_type != DT_DIR ||
- strcmp(dent->d_name, ".") == 0 ||
- strcmp(dent->d_name, "..") == 0 ||
- strcmp(dent->d_name, "ftrace") == 0 ||
- !system_in_tp_list(dent->d_name, tps))
- continue;
- count++;
- }
+ read_event_files_system(tps, "ftrace");

+ /* systems count */
+ count_pos = lseek(output_fd, 0, SEEK_CUR);
write_or_die(&count, 4);

- rewinddir(dir);
- while ((dent = readdir(dir))) {
- if (dent->d_type != DT_DIR ||
- strcmp(dent->d_name, ".") == 0 ||
- strcmp(dent->d_name, "..") == 0 ||
- strcmp(dent->d_name, "ftrace") == 0 ||
- !system_in_tp_list(dent->d_name, tps))
- continue;
- sys = malloc_or_die(strlen(path) + strlen(dent->d_name) + 2);
- sprintf(sys, "%s/%s", path, dent->d_name);
- ret = stat(sys, &st);
- if (ret >= 0) {
- write_or_die(dent->d_name, strlen(dent->d_name) + 1);
- copy_event_system(sys, tps);
+ while (tps) {
+ if (!tps->done) {
+ write_or_die(tps->system, strlen(tps->system) + 1);
+ read_event_files_system(tps, tps->system);
+ count++;
}
- free(sys);
+
+ tps = tps->next;
}

- closedir(dir);
- put_tracing_file(path);
+ if (pwrite(output_fd, &count, 4, count_pos) < 0)
+ die("write");
}

static void read_proc_kallsyms(void)
@@ -387,6 +349,37 @@ static void read_proc_kallsyms(void)
record_file(path, 4);
}

+static void tracing_data_header(void)
+{
+ char buf[50];
+
+ /* just guessing this is someone's birthday.. ;) */
+ buf[0] = 23;
+ buf[1] = 8;
+ buf[2] = 68;
+ memcpy(buf + 3, "tracing", 7);
+
+ write_or_die(buf, 10);
+
+ write_or_die(VERSION, strlen(VERSION) + 1);
+
+ /* save endian */
+ if (bigendian())
+ buf[0] = 1;
+ else
+ buf[0] = 0;
+
+ write_or_die(buf, 1);
+
+ /* save size of long */
+ buf[0] = sizeof(long);
+ write_or_die(buf, 1);
+
+ /* save page_size */
+ page_size = sysconf(_SC_PAGESIZE);
+ write_or_die(&page_size, 4);
+}
+
static void read_ftrace_printk(void)
{
unsigned int size;
@@ -441,7 +434,6 @@ bool have_tracepoints(struct list_head *pattrs)

int read_tracing_data(int fd, struct list_head *pattrs)
{
- char buf[BUFSIZ];
struct tracepoint_path *tps = get_tracepoints_path(pattrs);

/*
@@ -452,33 +444,8 @@ int read_tracing_data(int fd, struct list_head *pattrs)

output_fd = fd;

- buf[0] = 23;
- buf[1] = 8;
- buf[2] = 68;
- memcpy(buf + 3, "tracing", 7);
-
- write_or_die(buf, 10);
-
- write_or_die(VERSION, strlen(VERSION) + 1);
-
- /* save endian */
- if (bigendian())
- buf[0] = 1;
- else
- buf[0] = 0;
-
- write_or_die(buf, 1);
-
- /* save size of long */
- buf[0] = sizeof(long);
- write_or_die(buf, 1);
-
- /* save page_size */
- page_size = sysconf(_SC_PAGESIZE);
- write_or_die(&page_size, 4);
-
+ tracing_data_header();
read_header_files();
- read_ftrace_files(tps);
read_event_files(tps);
read_proc_kallsyms();
read_ftrace_printk();
--
1.7.4