[Devel] [PATCH vz9 04/20] /proc/<pid>/vz_latency: Add scheduling stats
Nikita Yushchenko
nikita.yushchenko at virtuozzo.com
Wed Oct 13 18:26:15 MSK 2021
From: Andrey Ryabinin <aryabinin at virtuozzo.com>
Add scheduling latencies to /proc/<pid>/vz_latency.
They are the same as alloc latencies - total cumulative
latency, number of schedule events, and latency maximum
in the last 2 minutes.
The sysctl kernel.sched_schedstats must be enabled to
see these stats.
https://jira.sw.ru/browse/PSBM-87797
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
Cc: Pavel Borzenkov <Pavel.Borzenkov at acronis.com>
Reviewed-by: Denis V. Lunev <den at openvz.org>
Rebase to vz8:
- Add new argument to update_sched_lat. It was reworked during previous
ports to have only time delta, which is unsufficient for
update_maxlat.
(cherry-picked from vz7 commit 0ed8df6d0d18 ("/proc/<pid>/vz_latency:
Add scheduling stats"))
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
(cherry-picked from vz8 commit f11900f53ba3 ("/proc/<pid>/vz_latency:
Add scheduling stats"))
Signed-off-by: Nikita Yushchenko <nikita.yushchenko at virtuozzo.com>
---
fs/proc/base.c | 18 ++++++++++++++++--
include/linux/kstat.h | 5 +++++
include/linux/sched.h | 2 +-
include/linux/sched/signal.h | 2 +-
kernel/exit.c | 6 ++----
kernel/sched/fair.c | 13 +++++++++----
6 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 5a98e4bdd5d3..b1609703b90a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -558,13 +558,18 @@ static const char *alloc_descr[] = {
"allocatomic:",
"alloc:",
"allocmp:",
+ "scheduling:",
};
static const int alloc_types[] = {
KSTAT_ALLOCSTAT_ATOMIC,
KSTAT_ALLOCSTAT_LOW,
KSTAT_ALLOCSTAT_LOW_MP,
+ KSTAT_SCHED,
};
+extern struct static_key sched_schedstats;
+# define schedstat_enabled() static_key_false(&sched_schedstats)
+
static int proc_tid_vz_lat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -573,9 +578,13 @@ static int proc_tid_vz_lat(struct seq_file *m, struct pid_namespace *ns,
seq_printf(m, "%-12s %20s %20s %20s\n",
"Type", "Total_lat", "Calls", "Max (2min)");
- for (i = 0; i < ARRAY_SIZE(alloc_types); i++)
+ for (i = 0; i < ARRAY_SIZE(alloc_types); i++) {
+ if (alloc_types[i] == KSTAT_SCHED && !schedstat_enabled())
+ continue;
lastlat_seq_show(m, alloc_descr[i],
&task->alloc_lat[alloc_types[i]]);
+ }
+
return 0;
}
@@ -615,15 +624,20 @@ static int proc_tgid_vz_lat(struct seq_file *m, struct pid_namespace *ns,
maxlats[i] = maxlat;
}
+
unlock_task_sighand(task, &flags);
}
seq_printf(m, "%-12s %20s %20s %20s\n",
"Type", "Total_lat", "Calls", "Max (2min)");
- for (i = 0; i < ARRAY_SIZE(alloc_types); i++)
+ for (i = 0; i < ARRAY_SIZE(alloc_types); i++) {
+ if (alloc_types[i] == KSTAT_SCHED && !schedstat_enabled())
+ continue;
+
seq_printf(m, "%-12s %20Lu %20Lu %20Lu\n", alloc_descr[i],
lat[i], count[i], maxlats[i]);
+ }
return 0;
}
diff --git a/include/linux/kstat.h b/include/linux/kstat.h
index c25de162a00b..e33f70fbed42 100644
--- a/include/linux/kstat.h
+++ b/include/linux/kstat.h
@@ -17,6 +17,8 @@ enum {
KSTAT_ALLOCSTAT_LOW_MP,
KSTAT_ALLOCSTAT_HIGH_MP,
KSTAT_ALLOCSTAT_NR,
+ KSTAT_SCHED = KSTAT_ALLOCSTAT_NR,
+ KSTAT_NR,
};
struct kstat_perf_snap_struct {
@@ -55,4 +57,7 @@ struct kstat_lat_pcpu_struct {
u64 avg[3];
};
+void update_maxlat(struct kstat_lat_snap_struct *alloc_lat,
+ u64 lat, unsigned long time);
+
#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e0a562d76aa1..81ae96f909a2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1244,7 +1244,7 @@ struct task_struct {
struct tlbflush_unmap_batch tlb_ubc;
#ifdef CONFIG_VE
- struct kstat_lat_snap_struct alloc_lat[KSTAT_ALLOCSTAT_NR];
+ struct kstat_lat_snap_struct alloc_lat[KSTAT_NR];
#endif
union {
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index b48fba3fc9dd..9e5b8add41d1 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -209,7 +209,7 @@ struct signal_struct {
struct taskstats *stats;
#endif
#ifdef CONFIG_VE
- struct kstat_lat_snap_struct alloc_lat[KSTAT_ALLOCSTAT_NR];
+ struct kstat_lat_snap_struct alloc_lat[KSTAT_NR];
#endif
#ifdef CONFIG_AUDIT
unsigned audit_tty;
diff --git a/kernel/exit.c b/kernel/exit.c
index 67a26b302e61..1185fc9027af 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -750,16 +750,13 @@ static void check_stack_usage(void)
static inline void check_stack_usage(void) {}
#endif
-void update_maxlat(struct kstat_lat_snap_struct *alloc_lat,
- u64 lat, unsigned long time);
-
void kstat_add_dying(struct task_struct *tsk)
{
#ifdef CONFIG_VE
int i;
spin_lock_irq(&tsk->sighand->siglock);
- for (i = 0; i < KSTAT_ALLOCSTAT_NR; i++) {
+ for (i = 0; i < KSTAT_NR; i++) {
int j;
tsk->signal->alloc_lat[i].totlat += tsk->alloc_lat[i].totlat;
@@ -773,6 +770,7 @@ void kstat_add_dying(struct task_struct *tsk)
}
}
}
+
spin_unlock_irq(&tsk->sighand->siglock);
#endif
}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index db7eb593e9db..2afe9f705aa6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -937,11 +937,15 @@ update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
__schedstat_set(se->statistics.wait_start, wait_start);
}
-static inline void update_sched_lat(struct task_struct *t, u64 delta)
+static inline void update_sched_lat(struct task_struct *t, u64 delta, u64 now)
{
#ifdef CONFIG_VE
KSTAT_LAT_PCPU_ADD(&kstat_glob.sched_lat, delta);
KSTAT_LAT_PCPU_ADD(&t->task_ve->sched_lat_ve, delta);
+
+ t->alloc_lat[KSTAT_SCHED].totlat += delta;
+ t->alloc_lat[KSTAT_SCHED].count++;
+ update_maxlat(&t->alloc_lat[KSTAT_SCHED], delta, now);
#endif
}
@@ -949,7 +953,7 @@ static inline void
update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct task_struct *p;
- u64 delta;
+ u64 delta, now;
if (!schedstat_enabled())
return;
@@ -963,7 +967,8 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
if (unlikely(!schedstat_val(se->statistics.wait_start)))
return;
- delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start);
+ now = rq_clock(rq_of(cfs_rq));
+ delta = now - schedstat_val(se->statistics.wait_start);
if (entity_is_task(se)) {
p = task_of(se);
@@ -977,7 +982,7 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
return;
}
trace_sched_stat_wait(p, delta);
- update_sched_lat(p, delta);
+ update_sched_lat(p, delta, now);
}
__schedstat_set(se->statistics.wait_max,
--
2.30.2
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