From: Suren Baghdasaryan <surenb@google.com>
To: yang.yang29@zte.com.cn
Cc: hannes@cmpxchg.org, mingo@redhat.com,
linux-kernel@vger.kernel.org, juri.lelli@redhat.com
Subject: Re: [PATCH linux-next] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary
Date: Wed, 13 Sep 2023 23:01:01 +0000 [thread overview]
Message-ID: <CAJuCfpF_gSdfk_csny-6p661gfGy41w0V2QwoCSY02KdeXMLEA@mail.gmail.com> (raw)
In-Reply-To: <202309132044261713252@zte.com.cn>
On Wed, Sep 13, 2023 at 12:44 PM <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 have not changed.
>
> Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
> ---
> kernel/sched/psi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index 81fca77397f6..e4463bb267c3 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -701,7 +701,7 @@ static void psi_rtpoll_work(struct psi_group *group)
> goto out;
> }
>
> - if (now >= group->rtpoll_next_update) {
> + if ((changed_states & group->rtpoll_states) && (now >= group->rtpoll_next_update)) {
With this additional condition group->rtpoll_next_update will not be
updated if states do not change and later on we will have a call to
psi_schedule_rtpoll_work() with the delay calculated as
"nsecs_to_jiffies(group->rtpoll_next_update - now) + 1". With
group->rtpoll_next_update not updated, we can end up with a negative
delay. I don't think that's your intention here, it is?
> group->rtpoll_next_update = update_triggers(group, now, &update_total, PSI_POLL);
> if (update_total)
> memcpy(group->rtpoll_total, group->total[PSI_POLL],
> --
> 2.25.1
next prev parent reply other threads:[~2023-09-13 23:01 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 [this message]
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
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
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