Re: [PATCH 02/27] perf tools: Add comm string into struct thread_map

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Jun 23, 2015 at 12:36:03AM +0200, Jiri Olsa escreveu:
> Adding support to hold comm name together with pids in
> 'struct thread_map'. It will be useful for --per-thread
> option to display task pid together with task name.
> 
> Getting the task name from /proc/$pid/comm.

Do we really need to read this all the time? Or just for tools that need
this?

Can't we have a thread_map__read_comms(map);

That we can make this specific --per-thread option in 'stat' call?

Applied the first patch after breaking it into two, one to add the
accessors and the other to transform the map entries into a struct.

Pushed to perf/core already.

- 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       | 67 ++++++++++++++++++++++++++++++++++++--
>  tools/perf/util/thread_map.h       | 12 +++++++
>  3 files changed, 77 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/python-ext-sources b/tools/perf/util/python-ext-sources
> index 5925fec90562..e23ded40c79e 100644
> --- a/tools/perf/util/python-ext-sources
> +++ b/tools/perf/util/python-ext-sources
> @@ -20,3 +20,4 @@ util/stat.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 7a4be3754d05..5b2f2495af26 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 +31,51 @@ 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) {
> +		/*
> +		 * We're reading 16 bytes, while filename__read_str
> +		 * allocates data per BUFSIZ bytes, so we can safely
> +		 * mark the end of the string.
> +		 */
> +		(*comm)[size] = 0;
> +		rtrim(*comm);
> +	}
> +
> +	free(path);
> +	return err;
> +}
> +
> +static void comm_init(struct thread_map *map, int i)
> +{
> +	pid_t pid = thread_map__pid(map, i);
> +	char *comm = NULL;
> +
> +	/* dummy pid comm initialization */
> +	if (pid == -1) {
> +		thread_map__set_comm(map, i, strdup("dummy"));
> +		return;
> +	}
> +
> +	/*
> +	 * The comm name is like extra bonus ;-),
> +	 * so just warn if we fail for any reason.
> +	 */
> +	if (get_comm(&comm, pid))
> +		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
> +
> +	thread_map__set_comm(map, i, comm);
> +}
> +
>  struct thread_map *thread_map__new_by_pid(pid_t pid)
>  {
>  	struct thread_map *threads;
> @@ -44,8 +91,10 @@ 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__set_pid(threads, i, atoi(namelist[i]->d_name));
> +			comm_init(threads, i);
> +		}
>  		threads->nr = items;
>  	}
>  
> @@ -63,6 +112,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
>  	if (threads != NULL) {
>  		thread_map__set_pid(threads, 0, tid);
>  		threads->nr = 1;
> +		comm_init(threads, 0);
>  	}
>  
>  	return threads;
> @@ -126,6 +176,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
>  		for (i = 0; i < items; i++) {
>  			thread_map__set_pid(threads, threads->nr + i,
>  					    atoi(namelist[i]->d_name));
> +			comm_init(threads, threads->nr + i);
>  		}
>  
>  		for (i = 0; i < items; i++)
> @@ -202,8 +253,9 @@ static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
>  
>  		threads = nt;
>  
> -		for (i = 0; i < items; i++) {
> -			thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
> +		for (i = 0; i < items; i++, j++) {
> +			thread_map__set_pid(threads, j, atoi(namelist[i]->d_name));
> +			comm_init(threads, j);
>  			zfree(&namelist[i]);
>  		}
>  		threads->nr = total_tasks;
> @@ -231,6 +283,7 @@ struct thread_map *thread_map__new_dummy(void)
>  	if (threads != NULL) {
>  		thread_map__set_pid(threads, 0, -1);
>  		threads->nr = 1;
> +		comm_init(threads, 0);
>  	}
>  	return threads;
>  }
> @@ -271,6 +324,7 @@ static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
>  		threads = nt;
>  		thread_map__set_pid(threads, ntasks - 1, tid);
>  		threads->nr = ntasks;
> +		comm_init(threads, ntasks - 1);
>  	}
>  out:
>  	return threads;
> @@ -294,6 +348,13 @@ 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 b9f40679f589..0f67843475e6 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 {
> @@ -41,4 +42,15 @@ thread_map__set_pid(struct thread_map *map, int thread, pid_t pid)
>  {
>  	map->map[thread].pid = pid;
>  }
> +
> +static inline char *thread_map__comm(struct thread_map *map, int thread)
> +{
> +	return map->map[thread].comm;
> +}
> +
> +static inline void
> +thread_map__set_comm(struct thread_map *map, int thread, char *comm)
> +{
> +	map->map[thread].comm = comm;
> +}
>  #endif	/* __PERF_THREAD_MAP_H */
> -- 
> 1.9.3