diff options
| author | Wang Yaxin <wang.yaxin@zte.com.cn> | 2024-12-03 16:48:48 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-01-12 20:20:59 -0800 |
| commit | 658eb5ab916ddc92f294dbce8e3d449470be9f86 (patch) | |
| tree | a1cbd2699cb8f2b0cd2514649aa0df69619de1e7 /kernel/delayacct.c | |
| parent | 1e1857230c4879ae6ec37e1dbcbf6ce6217056b5 (diff) | |
delayacct: add delay max to record delay peak
Introduce the use cases of delay max, which can help quickly detect
potential abnormal delays in the system and record the types and specific
details of delay spikes.
Problem
========
Delay accounting can track the average delay of processes to show
system workload. However, when a process experiences a significant
delay, maybe a delay spike, which adversely affects performance,
getdelays can only display the average system delay over a period
of time. Yet, average delay is unhelpful for diagnosing delay peak.
It is not even possible to determine which type of delay has spiked,
as this information might be masked by the average delay.
Solution
=========
the 'delay max' can display delay peak since the system's startup,
which can record potential abnormal delays over time, including
the type of delay and the maximum delay. This is helpful for
quickly identifying crash caused by delay.
Use case
=========
bash# ./getdelays -d -p 244
print delayacct stats ON
PID 244
CPU count real total virtual total delay total delay average delay max
68 192000000 213676651 705643 0.010ms 0.306381ms
IO count delay total delay average delay max
0 0 0.000ms 0.000000ms
SWAP count delay total delay average delay max
0 0 0.000ms 0.000000ms
RECLAIM count delay total delay average delay max
0 0 0.000ms 0.000000ms
THRASHING count delay total delay average delay max
0 0 0.000ms 0.000000ms
COMPACT count delay total delay average delay max
0 0 0.000ms 0.000000ms
WPCOPY count delay total delay average delay max
235 15648284 0.067ms 0.263842ms
IRQ count delay total delay average delay max
0 0 0.000ms 0.000000ms
[wang.yaxin@zte.com.cn: update docs and fix some spelling errors]
Link: https://lkml.kernel.org/r/20241213192700771XKZ8H30OtHSeziGqRVMs0@zte.com.cn
Link: https://lkml.kernel.org/r/20241203164848805CS62CQPQWG9GLdQj2_BxS@zte.com.cn
Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Co-developed-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel/delayacct.c')
| -rw-r--r-- | kernel/delayacct.c | 37 |
1 files changed, 27 insertions, 10 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c index dead51de8eb5..23212a0c88e4 100644 --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -93,9 +93,9 @@ void __delayacct_tsk_init(struct task_struct *tsk) /* * Finish delay accounting for a statistic using its timestamps (@start), - * accumalator (@total) and @count + * accumulator (@total) and @count */ -static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count) +static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count, u64 *max) { s64 ns = local_clock() - *start; unsigned long flags; @@ -104,6 +104,8 @@ static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *cou raw_spin_lock_irqsave(lock, flags); *total += ns; (*count)++; + if (ns > *max) + *max = ns; raw_spin_unlock_irqrestore(lock, flags); } } @@ -122,7 +124,8 @@ void __delayacct_blkio_end(struct task_struct *p) delayacct_end(&p->delays->lock, &p->delays->blkio_start, &p->delays->blkio_delay, - &p->delays->blkio_count); + &p->delays->blkio_count, + &p->delays->blkio_delay_max); } int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) @@ -153,10 +156,11 @@ int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) d->cpu_count += t1; + d->cpu_delay_max = tsk->sched_info.max_run_delay; tmp = (s64)d->cpu_delay_total + t2; d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp; - tmp = (s64)d->cpu_run_virtual_total + t3; + d->cpu_run_virtual_total = (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp; @@ -164,20 +168,26 @@ int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) return 0; /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ - raw_spin_lock_irqsave(&tsk->delays->lock, flags); + d->blkio_delay_max = tsk->delays->blkio_delay_max; tmp = d->blkio_delay_total + tsk->delays->blkio_delay; d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; + d->swapin_delay_max = tsk->delays->swapin_delay_max; tmp = d->swapin_delay_total + tsk->delays->swapin_delay; d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; + d->freepages_delay_max = tsk->delays->freepages_delay_max; tmp = d->freepages_delay_total + tsk->delays->freepages_delay; d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp; + d->thrashing_delay_max = tsk->delays->thrashing_delay_max; tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay; d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp; + d->compact_delay_max = tsk->delays->compact_delay_max; tmp = d->compact_delay_total + tsk->delays->compact_delay; d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp; + d->wpcopy_delay_max = tsk->delays->wpcopy_delay_max; tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay; d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp; + d->irq_delay_max = tsk->delays->irq_delay_max; tmp = d->irq_delay_total + tsk->delays->irq_delay; d->irq_delay_total = (tmp < d->irq_delay_total) ? 0 : tmp; d->blkio_count += tsk->delays->blkio_count; @@ -213,7 +223,8 @@ void __delayacct_freepages_end(void) delayacct_end(¤t->delays->lock, ¤t->delays->freepages_start, ¤t->delays->freepages_delay, - ¤t->delays->freepages_count); + ¤t->delays->freepages_count, + ¤t->delays->freepages_delay_max); } void __delayacct_thrashing_start(bool *in_thrashing) @@ -235,7 +246,8 @@ void __delayacct_thrashing_end(bool *in_thrashing) delayacct_end(¤t->delays->lock, ¤t->delays->thrashing_start, ¤t->delays->thrashing_delay, - ¤t->delays->thrashing_count); + ¤t->delays->thrashing_count, + ¤t->delays->thrashing_delay_max); } void __delayacct_swapin_start(void) @@ -248,7 +260,8 @@ void __delayacct_swapin_end(void) delayacct_end(¤t->delays->lock, ¤t->delays->swapin_start, ¤t->delays->swapin_delay, - ¤t->delays->swapin_count); + ¤t->delays->swapin_count, + ¤t->delays->swapin_delay_max); } void __delayacct_compact_start(void) @@ -261,7 +274,8 @@ void __delayacct_compact_end(void) delayacct_end(¤t->delays->lock, ¤t->delays->compact_start, ¤t->delays->compact_delay, - ¤t->delays->compact_count); + ¤t->delays->compact_count, + ¤t->delays->compact_delay_max); } void __delayacct_wpcopy_start(void) @@ -274,7 +288,8 @@ void __delayacct_wpcopy_end(void) delayacct_end(¤t->delays->lock, ¤t->delays->wpcopy_start, ¤t->delays->wpcopy_delay, - ¤t->delays->wpcopy_count); + ¤t->delays->wpcopy_count, + ¤t->delays->wpcopy_delay_max); } void __delayacct_irq(struct task_struct *task, u32 delta) @@ -284,6 +299,8 @@ void __delayacct_irq(struct task_struct *task, u32 delta) raw_spin_lock_irqsave(&task->delays->lock, flags); task->delays->irq_delay += delta; task->delays->irq_count++; + if (delta > task->delays->irq_delay_max) + task->delays->irq_delay_max = delta; raw_spin_unlock_irqrestore(&task->delays->lock, flags); } |