[PATCH v2 4/4] perf sched: Commit to evsel__taskstate() to parse task state info

From: Ze Gao
Date: Mon Jan 22 2024 - 02:12:09 EST


Now that we have evsel__taskstate() which no longer relies on the
hardcoded task state string and has good backward compatibility,
we have a good reason to use it.

Note TASK_STATE_TO_CHAR_STR and task bitmasks are useless now so
we remove them for good. And now we pass the state info back and
forth in a symbolic char which explains itself well instead.

Signed-off-by: Ze Gao <zegao@xxxxxxxxxxx>
---
tools/perf/builtin-sched.c | 46 +++++++++-----------------------------
1 file changed, 10 insertions(+), 36 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index ced6fffe8110..f1d62f6b6cab 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -92,13 +92,6 @@ struct sched_atom {
struct task_desc *wakee;
};

-#define TASK_STATE_TO_CHAR_STR "RSDTtXZPI"
-
-/* task state bitmask, copied from include/linux/sched.h */
-#define TASK_RUNNING 0
-#define TASK_INTERRUPTIBLE 1
-#define TASK_UNINTERRUPTIBLE 2
-
enum thread_state {
THREAD_SLEEPING = 0,
THREAD_WAIT_CPU,
@@ -255,7 +248,7 @@ struct thread_runtime {
u64 total_preempt_time;
u64 total_delay_time;

- int last_state;
+ char last_state;

char shortname[3];
bool comm_changed;
@@ -425,7 +418,7 @@ static void add_sched_event_wakeup(struct perf_sched *sched, struct task_desc *t
}

static void add_sched_event_sleep(struct perf_sched *sched, struct task_desc *task,
- u64 timestamp, u64 task_state __maybe_unused)
+ u64 timestamp, const char task_state __maybe_unused)
{
struct sched_atom *event = get_new_event(task, timestamp);

@@ -849,7 +842,7 @@ static int replay_switch_event(struct perf_sched *sched,
*next_comm = evsel__strval(evsel, sample, "next_comm");
const u32 prev_pid = evsel__intval(evsel, sample, "prev_pid"),
next_pid = evsel__intval(evsel, sample, "next_pid");
- const u64 prev_state = evsel__intval(evsel, sample, "prev_state");
+ const char prev_state = evsel__taskstate(evsel, sample, "prev_state");
struct task_desc *prev, __maybe_unused *next;
u64 timestamp0, timestamp = sample->time;
int cpu = sample->cpu;
@@ -1039,13 +1032,6 @@ static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread)
return 0;
}

-static char sched_out_state(u64 prev_state)
-{
- const char *str = TASK_STATE_TO_CHAR_STR;
-
- return str[prev_state];
-}
-
static int
add_sched_out_event(struct work_atoms *atoms,
char run_state,
@@ -1121,7 +1107,7 @@ static int latency_switch_event(struct perf_sched *sched,
{
const u32 prev_pid = evsel__intval(evsel, sample, "prev_pid"),
next_pid = evsel__intval(evsel, sample, "next_pid");
- const u64 prev_state = evsel__intval(evsel, sample, "prev_state");
+ const char prev_state = evsel__taskstate(evsel, sample, "prev_state");
struct work_atoms *out_events, *in_events;
struct thread *sched_out, *sched_in;
u64 timestamp0, timestamp = sample->time;
@@ -1157,7 +1143,7 @@ static int latency_switch_event(struct perf_sched *sched,
goto out_put;
}
}
- if (add_sched_out_event(out_events, sched_out_state(prev_state), timestamp))
+ if (add_sched_out_event(out_events, prev_state, timestamp))
return -1;

in_events = thread_atoms_search(&sched->atom_root, sched_in, &sched->cmp_pid);
@@ -2022,24 +2008,12 @@ static void timehist_header(struct perf_sched *sched)
printf("\n");
}

-static char task_state_char(struct thread *thread, int state)
-{
- static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
- unsigned bit = state ? ffs(state) : 0;
-
- /* 'I' for idle */
- if (thread__tid(thread) == 0)
- return 'I';
-
- return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
-}
-
static void timehist_print_sample(struct perf_sched *sched,
struct evsel *evsel,
struct perf_sample *sample,
struct addr_location *al,
struct thread *thread,
- u64 t, int state)
+ u64 t, const char state)
{
struct thread_runtime *tr = thread__priv(thread);
const char *next_comm = evsel__strval(evsel, sample, "next_comm");
@@ -2080,7 +2054,7 @@ static void timehist_print_sample(struct perf_sched *sched,
print_sched_time(tr->dt_run, 6);

if (sched->show_state)
- printf(" %5c ", task_state_char(thread, state));
+ printf(" %5c ", thread->tid == 0 ? 'I' : state);

if (sched->show_next) {
snprintf(nstr, sizeof(nstr), "next: %s[%d]", next_comm, next_pid);
@@ -2152,9 +2126,9 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
else if (r->last_time) {
u64 dt_wait = tprev - r->last_time;

- if (r->last_state == TASK_RUNNING)
+ if (r->last_state == 'R')
r->dt_preempt = dt_wait;
- else if (r->last_state == TASK_UNINTERRUPTIBLE)
+ else if (r->last_state == 'D')
r->dt_iowait = dt_wait;
else
r->dt_sleep = dt_wait;
@@ -2579,7 +2553,7 @@ static int timehist_sched_change_event(struct perf_tool *tool,
struct thread_runtime *tr = NULL;
u64 tprev, t = sample->time;
int rc = 0;
- int state = evsel__intval(evsel, sample, "prev_state");
+ const char state = evsel__taskstate(evsel, sample, "prev_state");

addr_location__init(&al);
if (machine__resolve(machine, &al, sample) < 0) {
--
2.41.0