LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Huaixin Chang <changhuaixin@linux.alibaba.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, anderson@cs.unc.edu, baruah@wustl.edu,
	bsegall@google.com, changhuaixin@linux.alibaba.com,
	dietmar.eggemann@arm.com, dtcccc@linux.alibaba.com,
	juri.lelli@redhat.com, khlebnikov@yandex-team.ru,
	luca.abeni@santannapisa.it, mgorman@suse.de, mingo@redhat.com,
	odin@uged.al, odin@ugedal.com, pauld@redhead.com, pjt@google.com,
	rostedt@goodmis.org, shanpeic@linux.alibaba.com, tj@kernel.org,
	tommaso.cucinotta@santannapisa.it, vincent.guittot@linaro.org,
	xiyou.wangcong@gmail.com
Subject: [PATCH 1/2] sched/fair: Add cfs bandwidth burst statistics
Date: Mon, 16 Aug 2021 15:08:48 +0800	[thread overview]
Message-ID: <20210816070849.3153-2-changhuaixin@linux.alibaba.com> (raw)
In-Reply-To: <20210816070849.3153-1-changhuaixin@linux.alibaba.com>

Two new statistics are introduced to show the internal of burst feature
and explain why burst helps or not.

nr_bursts:  number of periods bandwidth burst occurs
burst_usec: cumulative wall-time that any cpus has
	    used above quota in respective periods

Co-developed-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Co-developed-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 kernel/sched/core.c  | 13 ++++++++++---
 kernel/sched/fair.c  |  9 +++++++++
 kernel/sched/sched.h |  3 +++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d9ff40f4661..9a286c8a1354 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10088,6 +10088,9 @@ static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
 		seq_printf(sf, "wait_sum %llu\n", ws);
 	}
 
+	seq_printf(sf, "nr_bursts %d\n", cfs_b->nr_burst);
+	seq_printf(sf, "burst_usec %llu\n", cfs_b->burst_time);
+
 	return 0;
 }
 #endif /* CONFIG_CFS_BANDWIDTH */
@@ -10184,16 +10187,20 @@ static int cpu_extra_stat_show(struct seq_file *sf,
 	{
 		struct task_group *tg = css_tg(css);
 		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
-		u64 throttled_usec;
+		u64 throttled_usec, burst_usec;
 
 		throttled_usec = cfs_b->throttled_time;
 		do_div(throttled_usec, NSEC_PER_USEC);
+		burst_usec = cfs_b->burst_time;
+		do_div(burst_usec, NSEC_PER_USEC);
 
 		seq_printf(sf, "nr_periods %d\n"
 			   "nr_throttled %d\n"
-			   "throttled_usec %llu\n",
+			   "throttled_usec %llu\n"
+			   "nr_bursts %d\n"
+			   "burst_usec %llu\n",
 			   cfs_b->nr_periods, cfs_b->nr_throttled,
-			   throttled_usec);
+			   throttled_usec, cfs_b->nr_burst, burst_usec);
 	}
 #endif
 	return 0;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 44c452072a1b..464371f364f1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4655,11 +4655,20 @@ static inline u64 sched_cfs_bandwidth_slice(void)
  */
 void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
 {
+	s64 runtime;
+
 	if (unlikely(cfs_b->quota == RUNTIME_INF))
 		return;
 
 	cfs_b->runtime += cfs_b->quota;
+	runtime = cfs_b->runtime_snap - cfs_b->runtime;
+	if (runtime > 0) {
+		cfs_b->burst_time += runtime;
+		cfs_b->nr_burst++;
+	}
+
 	cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst);
+	cfs_b->runtime_snap = cfs_b->runtime;
 }
 
 static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 14a41a243f7b..80e4322727b4 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -367,6 +367,7 @@ struct cfs_bandwidth {
 	u64			quota;
 	u64			runtime;
 	u64			burst;
+	u64			runtime_snap;
 	s64			hierarchical_quota;
 
 	u8			idle;
@@ -379,7 +380,9 @@ struct cfs_bandwidth {
 	/* Statistics: */
 	int			nr_periods;
 	int			nr_throttled;
+	int			nr_burst;
 	u64			throttled_time;
+	u64			burst_time;
 #endif
 };
 
-- 
2.14.4.44.g2045bb6


  reply	other threads:[~2021-08-16  7:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16  7:08 [PATCH 0/2] Add statistics and document for cfs bandwidth burst Huaixin Chang
2021-08-16  7:08 ` Huaixin Chang [this message]
2021-08-23 18:32   ` [PATCH 1/2] sched/fair: Add cfs bandwidth burst statistics Daniel Jordan
2021-08-23 19:03     ` Tejun Heo
2021-08-16  7:08 ` [PATCH 2/2] sched/fair: Add document for burstable CFS bandwidth Huaixin Chang
2021-08-23 20:53   ` Daniel Jordan
  -- strict thread matches above, loose matches on Subject: below --
2021-08-30  3:22 [PATCH 0/2 v2] Add statistics and document for cfs_b burst Huaixin Chang
2021-08-30  3:22 ` [PATCH 1/2] sched/fair: Add cfs bandwidth burst statistics Huaixin Chang
2021-09-03 18:47   ` Benjamin Segall
2021-07-30  7:09 [PATCH 0/2] Add statistics and ducument for cfs bandwidth burst Huaixin Chang
2021-07-30  7:09 ` [PATCH 1/2] sched/fair: Add cfs bandwidth burst statistics Huaixin Chang
2021-08-12 12:18   ` changhuaixin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210816070849.3153-2-changhuaixin@linux.alibaba.com \
    --to=changhuaixin@linux.alibaba.com \
    --cc=anderson@cs.unc.edu \
    --cc=baruah@wustl.edu \
    --cc=bsegall@google.com \
    --cc=dietmar.eggemann@arm.com \
    --cc=dtcccc@linux.alibaba.com \
    --cc=juri.lelli@redhat.com \
    --cc=khlebnikov@yandex-team.ru \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luca.abeni@santannapisa.it \
    --cc=mgorman@suse.de \
    --cc=mingo@redhat.com \
    --cc=odin@uged.al \
    --cc=odin@ugedal.com \
    --cc=pauld@redhead.com \
    --cc=peterz@infradead.org \
    --cc=pjt@google.com \
    --cc=rostedt@goodmis.org \
    --cc=shanpeic@linux.alibaba.com \
    --cc=tj@kernel.org \
    --cc=tommaso.cucinotta@santannapisa.it \
    --cc=vincent.guittot@linaro.org \
    --cc=xiyou.wangcong@gmail.com \
    --subject='Re: [PATCH 1/2] sched/fair: Add cfs bandwidth burst statistics' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).