Re: [PATCH 04/30] perf tools: Add comm string into struct thread_map

Arnaldo Carvalho de Melo
2015-06-15T19:17:38Z

Em Sun, Jun 14, 2015 at 10:19:19AM +0200, Jiri Olsa escreveu:
> Adding support to hold comm name together with pids in
> 'struct thread_map'. It will be useful for --per-task
> option to display task pid together with task name.
>
> Getting the task name from /proc/$pid/comm.

Humm, so you want to extend the thread_map, that was just for pids, to
have some more info about the thread, if that is the case, why not
synthesize the whole thread, and have a pointer to 'struct thread', that
is the representation for a thread in perf instead of creating a new,
partial thing like 'thread_map_data'?

You wouldn't have to use the existing synthesizing code if that seems to
overkill, i.e. instead of having 'pid_t' as the array element in a
thread_map, you would have 'struct thread', i.e. the whole shebang, but
would just set what you need now, i.e. thread->pid and thread->comm, but
later could do the rest instead of recreating it in that thread_map_data
:-)

I.e. besides --per-task, don't you want --per-pid, --per-thread, or
other stuff that will use other thread characteristics?

That or rename that 'thread_map_data' to something like mini_thread,
...}.

Got carried away, but that was the reaction to that vague name
'thread_map_data' 8-)

Anyway, applied the first two, looking at the rest...

- Arnaldo

> Link: http://lkml.kernel.org/n/tip-pf6bgmbujukce0sgliuhj2f4@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/python-ext-sources | 1 +
> tools/perf/util/thread_map.c | 63 +++++++++++++++++++++++++++++++++++---
> tools/perf/util/thread_map.h | 2 ++
> 3 files changed, 62 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/python-ext-sources b/tools/perf/util/python-ext-sources
> index 4d28624a1eca..55ba8968a263 100644
> --- a/tools/perf/util/python-ext-sources
> +++ b/tools/perf/util/python-ext-sources
> @@ -19,3 +19,4 @@ util/rblist.c
> util/strlist.c
> util/trace-event.c
> ../../lib/rbtree.c
> +util/string.c
> diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
> index 7f03f9facfdd..f7a49a693d27 100644
> --- a/tools/perf/util/thread_map.c
> +++ b/tools/perf/util/thread_map.c
> @@ -8,8 +8,10 @@
> #include <unistd.h>
> #include "strlist.h"
> #include <string.h>
> +#include <api/fs/fs.h>
> #include "thread_map.h"
> #include "util.h"
> +#include "debug.h"
>
> /* Skip "." and ".." directories */
> static int filter(const struct dirent *dir)
> @@ -29,6 +31,44 @@ static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
>
> #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
>
> +static int get_comm(char **comm, pid_t pid)
> +{
> + char *path;
> + size_t size;
> + int err;
> +
> + if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
> + return -ENOMEM;
> +
> + err = filename__read_str(path, comm, &size);
> + if (!err)
> + rtrim(*comm);
> +
> + free(path);
> + return err;
> +}
> +
> +static void comm_init(struct thread_map *map, int i)
> +{
> + struct thread_map_data *data = &map->map[i];
> +
> + /*
> + * The comm name is like extra bonus ;-),
> + * so just warn if we fail for any reason.
> + */
> + data->comm = NULL;
> +
> + /* dummy pid comm initialization */
> + if (data->pid == -1) {
> + data->comm = strdup("dummy");
> + return;
> + }
> +
> + /* try to get pid's comm string */
> + if (get_comm(&data->comm, data->pid))
> + pr_warning("Couldn't resolve comm name for pid %d\n", data->pid);
> +}
> +
> struct thread_map *thread_map__new_by_pid(pid_t pid)
> {
> struct thread_map *threads;
> @@ -44,8 +84,10 @@ struct thread_map *thread_map__new_by_pid(pid_t pid)
>
> threads = thread_map__alloc(items);
> if (threads != NULL) {
> - for (i = 0; i < items; i++)
> + for (i = 0; i < items; i++) {
> thread_map__pid(threads, i) = atoi(namelist[i]->d_name);
> + comm_init(threads, i);
> + }
> threads->nr = items;
> }
>
> @@ -63,6 +105,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
> if (threads != NULL) {
> thread_map__pid(threads, 0) = tid;
> threads->nr = 1;
> + comm_init(threads, 0);
> }
>
> return threads;
> @@ -123,8 +166,10 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
> threads = tmp;
> }
>
> - for (i = 0; i < items; i++)
> + for (i = 0; i < items; i++) {
> thread_map__pid(threads, threads->nr + i) = atoi(namelist[i]->d_name);
> + comm_init(threads, threads->nr + i);
> + }
>
> for (i = 0; i < items; i++)
> zfree(&namelist[i]);
> @@ -200,8 +245,9 @@ static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
>
> threads = nt;
>
> - for (i = 0; i < items; i++) {
> - thread_map__pid(threads, j++) = atoi(namelist[i]->d_name);
> + for (i = 0; i < items; i++, j++) {
> + thread_map__pid(threads, j) = atoi(namelist[i]->d_name);
> + comm_init(threads, j);
> zfree(&namelist[i]);
> }
> threads->nr = total_tasks;
> @@ -229,6 +275,7 @@ struct thread_map *thread_map__new_dummy(void)
> if (threads != NULL) {
> thread_map__pid(threads, 0) = -1;
> threads->nr = 1;
> + comm_init(threads, 0);
> }
> return threads;
> }
> @@ -269,6 +316,7 @@ static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
> threads = nt;
> thread_map__pid(threads, ntasks - 1) = tid;
> threads->nr = ntasks;
> + comm_init(threads, ntasks - 1);
> }
> out:
> return threads;
> @@ -292,6 +340,13 @@ struct thread_map *thread_map__new_str(const char *pid, const char *tid,
>
> void thread_map__delete(struct thread_map *threads)
> {
> + int i;
> +
> + if (threads) {
> + for (i = 0; i < threads->nr; i++)
> + free(thread_map__comm(threads, i));
> + }
> +
> free(threads);
> }
>
> diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
> index 9377850c7b71..6933f9d316d9 100644
> --- a/tools/perf/util/thread_map.h
> +++ b/tools/perf/util/thread_map.h
> @@ -6,6 +6,7 @@
>
> struct thread_map_data {
> pid_t pid;
> + char *comm;
> };
>
> struct thread_map {
> @@ -14,6 +15,7 @@ struct thread_map {
> };
>
> #define thread_map__pid(__m, __t) __m->map[__t].pid
> +#define thread_map__comm(__m, __t) __m->map[__t].comm
>
> struct thread_map *thread_map__new_dummy(void);
> struct thread_map *thread_map__new_by_pid(pid_t pid);
> --
> 1.9.3