From: Suren Baghdasaryan <surenb@google.com>
To: gregkh@linuxfoundation.org
Cc: tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org,
axboe@kernel.dk, dennis@kernel.org, dennisszhou@gmail.com,
mingo@redhat.com, peterz@infradead.org,
akpm@linux-foundation.org, corbet@lwn.net,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@android.com, Suren Baghdasaryan <surenb@google.com>
Subject: [PATCH v5 4/7] psi: split update_stats into parts
Date: Fri, 8 Mar 2019 10:43:08 -0800 [thread overview]
Message-ID: <20190308184311.144521-5-surenb@google.com> (raw)
In-Reply-To: <20190308184311.144521-1-surenb@google.com>
Split update_stats into collect_percpu_times and update_averages for
collect_percpu_times to be reused later inside psi monitor.
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
kernel/sched/psi.c | 55 +++++++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 23 deletions(-)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 4fb4d9913bc8..337a445aefa3 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods,
avg[2] = calc_load(avg[2], EXP_300s, pct);
}
-static bool update_stats(struct psi_group *group)
+static bool collect_percpu_times(struct psi_group *group)
{
u64 deltas[NR_PSI_STATES - 1] = { 0, };
- unsigned long missed_periods = 0;
unsigned long nonidle_total = 0;
- u64 now, expires, period;
int cpu;
int s;
- mutex_lock(&group->avgs_lock);
-
/*
* Collect the per-cpu time buckets and average them into a
* single time sample that is normalized to wallclock time.
@@ -317,11 +313,18 @@ static bool update_stats(struct psi_group *group)
for (s = 0; s < NR_PSI_STATES - 1; s++)
group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL));
+ return nonidle_total;
+}
+
+static u64 update_averages(struct psi_group *group, u64 now)
+{
+ unsigned long missed_periods = 0;
+ u64 expires, period;
+ u64 avg_next_update;
+ int s;
+
/* avgX= */
- now = sched_clock();
expires = group->avg_next_update;
- if (now < expires)
- goto out;
if (now - expires >= psi_period)
missed_periods = div_u64(now - expires, psi_period);
@@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group)
* But the deltas we sample out of the per-cpu buckets above
* are based on the actual time elapsing between clock ticks.
*/
- group->avg_next_update = expires + ((1 + missed_periods) * psi_period);
+ avg_next_update = expires + ((1 + missed_periods) * psi_period);
period = now - (group->avg_last_update + (missed_periods * psi_period));
group->avg_last_update = now;
@@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group)
group->avg_total[s] += sample;
calc_avgs(group->avg[s], missed_periods, sample, period);
}
-out:
- mutex_unlock(&group->avgs_lock);
- return nonidle_total;
+
+ return avg_next_update;
}
static void psi_avgs_work(struct work_struct *work)
@@ -372,10 +374,16 @@ static void psi_avgs_work(struct work_struct *work)
struct delayed_work *dwork;
struct psi_group *group;
bool nonidle;
+ u64 now;
dwork = to_delayed_work(work);
group = container_of(dwork, struct psi_group, avgs_work);
+ mutex_lock(&group->avgs_lock);
+
+ now = sched_clock();
+
+ nonidle = collect_percpu_times(group);
/*
* If there is task activity, periodically fold the per-cpu
* times and feed samples into the running averages. If things
@@ -384,18 +392,15 @@ static void psi_avgs_work(struct work_struct *work)
* go - see calc_avgs() and missed_periods.
*/
- nonidle = update_stats(group);
-
if (nonidle) {
- unsigned long delay = 0;
- u64 now;
-
- now = sched_clock();
- if (group->avg_next_update > now)
- delay = nsecs_to_jiffies(
- group->avg_next_update - now) + 1;
- schedule_delayed_work(dwork, delay);
+ if (now >= group->avg_next_update)
+ group->avg_next_update = update_averages(group, now);
+
+ schedule_delayed_work(dwork, nsecs_to_jiffies(
+ group->avg_next_update - now) + 1);
}
+
+ mutex_unlock(&group->avgs_lock);
}
static void record_times(struct psi_group_cpu *groupc, int cpu,
@@ -711,7 +716,11 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
if (static_branch_likely(&psi_disabled))
return -EOPNOTSUPP;
- update_stats(group);
+ /* Update averages before reporting them */
+ mutex_lock(&group->avgs_lock);
+ collect_percpu_times(group);
+ update_averages(group, sched_clock());
+ mutex_unlock(&group->avgs_lock);
for (full = 0; full < 2 - (res == PSI_CPU); full++) {
unsigned long avg[3];
--
2.21.0.360.g471c308f928-goog
next prev parent reply other threads:[~2019-03-08 18:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-08 18:43 [PATCH v5 0/7] psi: pressure stall monitors v5 Suren Baghdasaryan
2019-03-08 18:43 ` [PATCH v5 1/7] psi: introduce state_mask to represent stalled psi states Suren Baghdasaryan
2019-03-08 18:43 ` [PATCH v5 2/7] psi: make psi_enable static Suren Baghdasaryan
2019-03-08 18:43 ` [PATCH v5 3/7] psi: rename psi fields in preparation for psi trigger addition Suren Baghdasaryan
2019-03-08 18:43 ` Suren Baghdasaryan [this message]
2019-03-08 18:43 ` [PATCH v5 5/7] psi: track changed states Suren Baghdasaryan
2019-03-08 18:43 ` [PATCH v5 6/7] refactor header includes to allow kthread.h inclusion in psi_types.h Suren Baghdasaryan
2019-03-09 20:49 ` kbuild test robot
2019-03-09 23:12 ` kbuild test robot
2019-03-08 18:43 ` [PATCH v5 7/7] psi: introduce psi monitor Suren Baghdasaryan
2019-03-19 22:51 ` [PATCH v5 0/7] psi: pressure stall monitors v5 Minchan Kim
2019-03-20 0:03 ` Suren Baghdasaryan
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=20190308184311.144521-5-surenb@google.com \
--to=surenb@google.com \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=cgroups@vger.kernel.org \
--cc=corbet@lwn.net \
--cc=dennis@kernel.org \
--cc=dennisszhou@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@android.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lizefan@huawei.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tj@kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).