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Date: Sat, 2 Dec 2017 12:53:09 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v5 10/12] perf util: Reuse thread_map__new_by_uid to
enumerate threads from /proc
On 12/1/2017 11:02 PM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Dec 01, 2017 at 11:44:25AM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Fri, Dec 01, 2017 at 06:57:34PM +0800, Jin Yao escreveu:
>>> Perf already has a function thread_map__new_by_uid() which can
>>> enumerate all threads from /proc by uid.
>>>
>>> This patch creates a static function enumerate_threads() which
>>> reuses the common code in thread_map__new_by_uid() to enumerate
>>> threads from /proc.
>>>
>>> The enumerate_threads() is shared by thread_map__new_by_uid()
>>> and a new function thread_map__new_threads().
>>>
>>> The new function thread_map__new_threads() is called to enumerate
>>> all threads from /proc.
>>>
>>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>>> ---
>>> tools/perf/tests/thread-map.c | 2 +-
>>> tools/perf/util/evlist.c | 3 ++-
>>> tools/perf/util/thread_map.c | 19 ++++++++++++++++---
>>> tools/perf/util/thread_map.h | 3 ++-
>>> 4 files changed, 21 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/tools/perf/tests/thread-map.c b/tools/perf/tests/thread-map.c
>>> index dbcb6a1..4de1939 100644
>>> --- a/tools/perf/tests/thread-map.c
>>> +++ b/tools/perf/tests/thread-map.c
>>> @@ -105,7 +105,7 @@ int test__thread_map_remove(struct test *test __maybe_unused, int subtest __mayb
>>> TEST_ASSERT_VAL("failed to allocate map string",
>>> asprintf(&str, "%d,%d", getpid(), getppid()) >= 0);
>>>
>>> - threads = thread_map__new_str(str, NULL, 0);
>>> + threads = thread_map__new_str(str, NULL, 0, false);
>>>
>>> TEST_ASSERT_VAL("failed to allocate thread_map",
>>> threads);
>>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
>>> index 199bb82..05b8f2b 100644
>>> --- a/tools/perf/util/evlist.c
>>> +++ b/tools/perf/util/evlist.c
>>> @@ -1102,7 +1102,8 @@ int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
>>> struct cpu_map *cpus;
>>> struct thread_map *threads;
>>>
>>> - threads = thread_map__new_str(target->pid, target->tid, target->uid);
>>> + threads = thread_map__new_str(target->pid, target->tid, target->uid,
>>> + target->per_thread);
>>>
>>> if (!threads)
>>> return -1;
>>> diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
>>> index be0d5a7..5672268 100644
>>> --- a/tools/perf/util/thread_map.c
>>> +++ b/tools/perf/util/thread_map.c
>>> @@ -92,7 +92,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
>>> return threads;
>>> }
>>>
>>> -struct thread_map *thread_map__new_by_uid(uid_t uid)
>>> +static struct thread_map *enumerate_threads(uid_t uid)
>>> {
>>> DIR *proc;
>>> int max_threads = 32, items, i;
>>> @@ -124,7 +124,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
>>> if (stat(path, &st) != 0)
>>> continue;
>>
>> Look, for the case where you want all threads enumerated you will incur
>> the above stat() cost for all of them and will not use it at all...
>>
>> And new_threads() seems vague, I'm using the ter used by 'perf record'
>> for system wide sampling, see the patch below:
>>
>
> The one below even compiles, I'll push what I merged already and we can
> continue from there:
>
> [acme@...et linux]$ git log --oneline -3
> 5cc4fc8994eb (HEAD -> perf/core) perf thread_map: Add method to map all threads in the system
> 9e49c22bd4d8 perf stat: Add rbtree node_delete op
> 1c92e3226546 perf rblist: Create rblist__exit() function
> [acme@...et linux]$
>
>
Yes we can continue from these commits.
I just pull the branch perf/core from
https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git, but it
looks the new commits have not been synced.
Maybe I will wait to next week to see if the new commits are synced and
then continue the work.
Thanks
Jin Yao
> commit 5cc4fc8994eb3f3af1950f3b726b6008900c7b06
> Author: Arnaldo Carvalho de Melo <acme@...hat.com>
> Date: Fri Dec 1 11:44:30 2017 -0300
>
> perf thread_map: Add method to map all threads in the system
>
> Reusing the thread_map__new_by_uid() proc scanning already in place to
> return a map with all threads in the system.
>
> Based-on-a-patch-by: Jin Yao <yao.jin@...ux.intel.com>
> Acked-by: Jiri Olsa <jolsa@...nel.org>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Andi Kleen <ak@...ux.intel.com>
> Cc: Kan Liang <kan.liang@...el.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Link: https://lkml.kernel.org/n/tip-khh28q0wwqbqtrk32bfe07hd@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
> index be0d5a736dea..2b653853eec2 100644
> --- a/tools/perf/util/thread_map.c
> +++ b/tools/perf/util/thread_map.c
> @@ -92,7 +92,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
> return threads;
> }
>
> -struct thread_map *thread_map__new_by_uid(uid_t uid)
> +static struct thread_map *__thread_map__new_all_cpus(uid_t uid)
> {
> DIR *proc;
> int max_threads = 32, items, i;
> @@ -113,7 +113,6 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
> while ((dirent = readdir(proc)) != NULL) {
> char *end;
> bool grow = false;
> - struct stat st;
> pid_t pid = strtol(dirent->d_name, &end, 10);
>
> if (*end) /* only interested in proper numerical dirents */
> @@ -121,11 +120,12 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
>
> snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
>
> - if (stat(path, &st) != 0)
> - continue;
> + if (uid != UINT_MAX) {
> + struct stat st;
>
> - if (st.st_uid != uid)
> - continue;
> + if (stat(path, &st) != 0 || st.st_uid != uid)
> + continue;
> + }
>
> snprintf(path, sizeof(path), "/proc/%d/task", pid);
> items = scandir(path, &namelist, filter, NULL);
> @@ -178,6 +178,16 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
> goto out_closedir;
> }
>
> +struct thread_map *thread_map__new_all_cpus(void)
> +{
> + return __thread_map__new_all_cpus(UINT_MAX);
> +}
> +
> +struct thread_map *thread_map__new_by_uid(uid_t uid)
> +{
> + return __thread_map__new_all_cpus(uid);
> +}
> +
> struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
> {
> if (pid != -1)
> diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
> index f15803985435..07a765fb22bb 100644
> --- a/tools/perf/util/thread_map.h
> +++ b/tools/perf/util/thread_map.h
> @@ -23,6 +23,7 @@ struct thread_map *thread_map__new_dummy(void);
> struct thread_map *thread_map__new_by_pid(pid_t pid);
> struct thread_map *thread_map__new_by_tid(pid_t tid);
> struct thread_map *thread_map__new_by_uid(uid_t uid);
> +struct thread_map *thread_map__new_all_cpus(void);
> struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid);
> struct thread_map *thread_map__new_event(struct thread_map_event *event);
>
>
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