Re: [PATCH v2 1/2] perf sched: move thread::shortname to thread_runtime

From: Arnaldo Carvalho de Melo
Date: Tue Mar 06 2018 - 09:10:34 EST


Em Tue, Mar 06, 2018 at 11:37:36AM +0800, changbin.du@xxxxxxxxx escreveu:
> From: Changbin Du <changbin.du@xxxxxxxxx>
>
> The thread::shortname only used by sched command, so move it
> to sched private structure.
>
> Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> ---
> tools/perf/builtin-sched.c | 95 +++++++++++++++++++++++++++-------------------
> tools/perf/util/thread.h | 1 -
> 2 files changed, 55 insertions(+), 41 deletions(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 83283fe..5bfc8d5 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -255,6 +255,8 @@ struct thread_runtime {
>
> int last_state;
> u64 migrations;
> +
> + char shortname[3];
> };

So, what we have for this struct right now is:

[root@jouet perf]# pahole -C thread_runtime ~/bin/perf
struct thread_runtime {
u64 last_time; /* 0 8 */
u64 dt_run; /* 8 8 */
u64 dt_sleep; /* 16 8 */
u64 dt_iowait; /* 24 8 */
u64 dt_preempt; /* 32 8 */
u64 dt_delay; /* 40 8 */
u64 ready_to_run; /* 48 8 */
struct stats run_stats; /* 56 40 */
/* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */
u64 total_run_time; /* 96 8 */
u64 total_sleep_time; /* 104 8 */
u64 total_iowait_time; /* 112 8 */
u64 total_preempt_time; /* 120 8 */
/* --- cacheline 2 boundary (128 bytes) --- */
u64 total_delay_time; /* 128 8 */
int last_state; /* 136 4 */

/* XXX 4 bytes hole, try to pack */

u64 migrations; /* 144 8 */

/* size: 152, cachelines: 3, members: 15 */
/* sum members: 148, holes: 1, sum holes: 4 */
/* last cacheline: 24 bytes */
};
[root@jouet perf]#

So I'll move this shortname member to just before 'migrations', then the
bool you'll add on the second patch to right after 'shortname' so that
this gets optimally packed.

Thanks,

- Arnaldo

> /* per event run time data */
> @@ -897,6 +899,37 @@ struct sort_dimension {
> struct list_head list;
> };
>
> +/*
> + * handle runtime stats saved per thread
> + */
> +static struct thread_runtime *thread__init_runtime(struct thread *thread)
> +{
> + struct thread_runtime *r;
> +
> + r = zalloc(sizeof(struct thread_runtime));
> + if (!r)
> + return NULL;
> +
> + init_stats(&r->run_stats);
> + thread__set_priv(thread, r);
> +
> + return r;
> +}
> +
> +static struct thread_runtime *thread__get_runtime(struct thread *thread)
> +{
> + struct thread_runtime *tr;
> +
> + tr = thread__priv(thread);
> + if (tr == NULL) {
> + tr = thread__init_runtime(thread);
> + if (tr == NULL)
> + pr_debug("Failed to malloc memory for runtime data.\n");
> + }
> +
> + return tr;
> +}
> +
> static int
> thread_lat_cmp(struct list_head *list, struct work_atoms *l, struct work_atoms *r)
> {
> @@ -1480,6 +1513,7 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
> {
> const u32 next_pid = perf_evsel__intval(evsel, sample, "next_pid");
> struct thread *sched_in;
> + struct thread_runtime *tr;
> int new_shortname;
> u64 timestamp0, timestamp = sample->time;
> s64 delta;
> @@ -1519,22 +1553,28 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
> if (sched_in == NULL)
> return -1;
>
> + tr = thread__get_runtime(sched_in);
> + if (tr == NULL) {
> + thread__put(sched_in);
> + return -1;
> + }
> +
> sched->curr_thread[this_cpu] = thread__get(sched_in);
>
> printf(" ");
>
> new_shortname = 0;
> - if (!sched_in->shortname[0]) {
> + if (!tr->shortname[0]) {
> if (!strcmp(thread__comm_str(sched_in), "swapper")) {
> /*
> * Don't allocate a letter-number for swapper:0
> * as a shortname. Instead, we use '.' for it.
> */
> - sched_in->shortname[0] = '.';
> - sched_in->shortname[1] = ' ';
> + tr->shortname[0] = '.';
> + tr->shortname[1] = ' ';
> } else {
> - sched_in->shortname[0] = sched->next_shortname1;
> - sched_in->shortname[1] = sched->next_shortname2;
> + tr->shortname[0] = sched->next_shortname1;
> + tr->shortname[1] = sched->next_shortname2;
>
> if (sched->next_shortname1 < 'Z') {
> sched->next_shortname1++;
> @@ -1552,6 +1592,7 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
> for (i = 0; i < cpus_nr; i++) {
> int cpu = sched->map.comp ? sched->map.comp_cpus[i] : i;
> struct thread *curr_thread = sched->curr_thread[cpu];
> + struct thread_runtime *curr_tr;
> const char *pid_color = color;
> const char *cpu_color = color;
>
> @@ -1569,9 +1610,14 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
> else
> color_fprintf(stdout, cpu_color, "*");
>
> - if (sched->curr_thread[cpu])
> - color_fprintf(stdout, pid_color, "%2s ", sched->curr_thread[cpu]->shortname);
> - else
> + if (sched->curr_thread[cpu]) {
> + curr_tr = thread__get_runtime(sched->curr_thread[cpu]);
> + if (curr_tr == NULL) {
> + thread__put(sched_in);
> + return -1;
> + }
> + color_fprintf(stdout, pid_color, "%2s ", curr_tr->shortname);
> + } else
> color_fprintf(stdout, color, " ");
> }
>
> @@ -1587,7 +1633,7 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
> pid_color = COLOR_PIDS;
>
> color_fprintf(stdout, pid_color, "%s => %s:%d",
> - sched_in->shortname, thread__comm_str(sched_in), sched_in->tid);
> + tr->shortname, thread__comm_str(sched_in), sched_in->tid);
> }
>
> if (sched->map.comp && new_cpu)
> @@ -2200,37 +2246,6 @@ static void save_idle_callchain(struct idle_thread_runtime *itr,
> callchain_cursor__copy(&itr->cursor, &callchain_cursor);
> }
>
> -/*
> - * handle runtime stats saved per thread
> - */
> -static struct thread_runtime *thread__init_runtime(struct thread *thread)
> -{
> - struct thread_runtime *r;
> -
> - r = zalloc(sizeof(struct thread_runtime));
> - if (!r)
> - return NULL;
> -
> - init_stats(&r->run_stats);
> - thread__set_priv(thread, r);
> -
> - return r;
> -}
> -
> -static struct thread_runtime *thread__get_runtime(struct thread *thread)
> -{
> - struct thread_runtime *tr;
> -
> - tr = thread__priv(thread);
> - if (tr == NULL) {
> - tr = thread__init_runtime(thread);
> - if (tr == NULL)
> - pr_debug("Failed to malloc memory for runtime data.\n");
> - }
> -
> - return tr;
> -}
> -
> static struct thread *timehist_get_thread(struct perf_sched *sched,
> struct perf_sample *sample,
> struct machine *machine,
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 40cfa36..14d44c3 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -26,7 +26,6 @@ struct thread {
> pid_t ppid;
> int cpu;
> refcount_t refcnt;
> - char shortname[3];
> bool comm_set;
> int comm_len;
> bool dead; /* if set thread has exited */
> --
> 2.7.4