From: Ingo Molnar <mingo@kernel.org>
To: yang.yang29@zte.com.cn
Cc: surenb@google.com, peterz@infradead.org, hannes@cmpxchg.org,
linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
mingo@redhat.com
Subject: Re: [PATCH linux-next v3 2/4] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary
Date: Wed, 11 Oct 2023 23:15:16 +0200 [thread overview]
Message-ID: <ZScQZLTssSfq19Jm@gmail.com> (raw)
In-Reply-To: <202310101641075436843@zte.com.cn>
* yang.yang29@zte.com.cn <yang.yang29@zte.com.cn> wrote:
> From: Yang Yang <yang.yang29@zte.com.cn>
>
> When psimon wakes up and there are no state changes for rtpoll_states,
> it's unnecessary to update triggers and rtpoll_total because the pressures
> being monitored by user had not changed.
> This will help to slightly reduce unnecessary computations of psi.
>
> Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
> Cc: Zhang Yunkai <zhang.yunkai@zte.com.cn>
> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> ---
> kernel/sched/psi.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index be853f227e40..143f8eb34f9d 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -704,11 +704,12 @@ static void psi_rtpoll_work(struct psi_group *group)
> }
>
> if (now >= group->rtpoll_next_update) {
> - update_triggers(group, now, &update_total, PSI_POLL);
> group->rtpoll_next_update = now + group->rtpoll_min_period;
> - if (update_total)
> + if (changed_states & group->rtpoll_states) {
> + update_triggers(group, now, &update_total, PSI_POLL);
> memcpy(group->rtpoll_total, group->total[PSI_POLL],
> sizeof(group->rtpoll_total));
> + }
Yeah, so I believe we may have been talking past each other for past
versions of this patch: why is this patch modifying the order of the
modification to group->rtpoll_next_update?
It should do the below sequence, nothing more - see the patch attached
below. This is basically a combination of patches #2 and #3.
And then the final patch removes the now superfluous 'update_total'
parameter, which is always true.
Here are the commits I applied to tip:sched/core:
e03dc9fa0663 sched/psi: Change update_triggers() to a 'void' function
...
80cc1d1d5ee3 sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes
3657680f38cd sched/psi: Delete the 'update_total' function parameter from update_triggers()
I rewrote the changelogs for readability.
Thanks,
Ingo
===================>
From: Yang Yang <yang.yang29@zte.com.cn>
Date: Tue, 10 Oct 2023 16:41:07 +0800
Subject: [PATCH] sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes
When psimon wakes up and there are no state changes for ->rtpoll_states,
it's unnecessary to update triggers and ->rtpoll_total because the pressures
being monitored by the user have not changed.
This will help to slightly reduce unnecessary computations of PSI.
[ mingo: Changelog updates ]
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310101641075436843@zte.com.cn
---
kernel/sched/psi.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index be853f227e40..79f8db0c6150 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -704,11 +704,12 @@ static void psi_rtpoll_work(struct psi_group *group)
}
if (now >= group->rtpoll_next_update) {
- update_triggers(group, now, &update_total, PSI_POLL);
- group->rtpoll_next_update = now + group->rtpoll_min_period;
- if (update_total)
+ if (changed_states & group->rtpoll_states) {
+ update_triggers(group, now, &update_total, PSI_POLL);
memcpy(group->rtpoll_total, group->total[PSI_POLL],
sizeof(group->rtpoll_total));
+ }
+ group->rtpoll_next_update = now + group->rtpoll_min_period;
}
psi_schedule_rtpoll_work(group,
next prev parent reply other threads:[~2023-10-11 21:15 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 12:44 [PATCH linux-next] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary yang.yang29
2023-09-13 23:01 ` Suren Baghdasaryan
2023-09-14 2:02 ` yang.yang29
2023-09-14 5:53 ` yang.yang29
2023-09-14 9:10 ` yang.yang29
2023-09-27 0:14 ` Suren Baghdasaryan
2023-09-27 1:56 ` yang.yang29
2023-09-30 22:32 ` Suren Baghdasaryan
2023-10-07 6:21 ` [PATCH linux-next v2] " yang.yang29
2023-10-09 10:49 ` Ingo Molnar
2023-10-09 12:19 ` [PATCH linux-next 0/3] sched/psi: Optimize the process of updating triggers and rtpoll_total yang.yang29
2023-10-09 12:24 ` [PATCH linux-next 1/3] sched/psi: Change update_triggers() to a void function yang.yang29
2023-10-09 12:48 ` Ingo Molnar
2023-10-09 12:59 ` [tip: sched/core] sched/psi: Change update_triggers() to a 'void' function tip-bot2 for Yang Yang
2023-10-09 12:30 ` [PATCH linux-next 2/3] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary yang.yang29
2023-10-09 12:52 ` Ingo Molnar
2023-10-09 17:42 ` Suren Baghdasaryan
2023-10-10 2:12 ` yang.yang29
2023-10-10 3:05 ` [PATCH linux-next v2 0/4] sched/psi: Optimize the process of updating triggers and rtpoll_total yang.yang29
2023-10-10 3:09 ` [PATCH linux-next v2 1/4] sched/psi: Change update_triggers() to a 'void' function yang.yang29
2023-10-10 7:38 ` Ingo Molnar
2023-10-10 8:31 ` [PATCH linux-next v3 0/4] sched/psi: Optimize the process of updating triggers and rtpoll_total yang.yang29
2023-10-10 8:36 ` [PATCH linux-next v3 1/4] sched/psi: Change update_triggers() to a 'void' function yang.yang29
2023-10-19 16:01 ` Suren Baghdasaryan
2023-10-10 8:41 ` [PATCH linux-next v3 2/4] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary yang.yang29
2023-10-11 21:15 ` Ingo Molnar [this message]
2023-10-12 2:13 ` yang.yang29
2023-10-19 16:04 ` Suren Baghdasaryan
2023-10-11 21:20 ` [tip: sched/core] sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes tip-bot2 for Yang Yang
2023-10-10 8:42 ` [PATCH linux-next v3 3/4] sched/psi: update rtpoll_next_update after update triggers and rtpoll_total yang.yang29
2023-10-19 16:07 ` Suren Baghdasaryan
2023-10-10 8:45 ` [PATCH linux-next v3 4/4] sched/psi: Delete the function parameter update_total of update_triggers() yang.yang29
2023-10-11 21:20 ` [tip: sched/core] sched/psi: Delete the 'update_total' function parameter from update_triggers() tip-bot2 for Yang Yang
2023-10-19 16:09 ` [PATCH linux-next v3 4/4] sched/psi: Delete the function parameter update_total of update_triggers() Suren Baghdasaryan
2023-10-10 3:20 ` [PATCH linux-next v2 2/4] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary yang.yang29
2023-10-10 3:24 ` [PATCH linux-next v2 3/4] sched/psi: update rtpoll_next_update after update triggers and rtpoll_total yang.yang29
2023-10-10 3:28 ` [PATCH linux-next v2 4/4] sched/psi: Delete the function parameter update_total of update_triggers() yang.yang29
2023-10-09 12:37 ` [PATCH linux-next 3/3] " yang.yang29
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=ZScQZLTssSfq19Jm@gmail.com \
--to=mingo@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=surenb@google.com \
--cc=yang.yang29@zte.com.cn \
/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).