From: Chengming Zhou <zhouchengming@bytedance.com>
To: Abel Wu <wuyun.abel@bytedance.com>,
hannes@cmpxchg.org, surenb@google.com, mingo@redhat.com,
peterz@infradead.org, tj@kernel.org, corbet@lwn.net,
akpm@linux-foundation.org, rdunlap@infradead.org
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
songmuchun@bytedance.com, cgroups@vger.kernel.org
Subject: Re: [PATCH 9/9] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure
Date: Fri, 22 Jul 2022 15:33:14 +0800 [thread overview]
Message-ID: <ab445d4d-70d2-9e6f-dd1d-9e71f00c1796@bytedance.com> (raw)
In-Reply-To: <5e5d41e2-5f89-8c52-11e5-0c55c5595a88@bytedance.com>
On 2022/7/22 15:14, Abel Wu wrote:
> On 7/22/22 2:13 PM, Chengming Zhou Wrote:
>> On 2022/7/22 11:30, Abel Wu wrote:
>>> Hi Chengming,
>>>
>>> On 7/21/22 12:04 PM, Chengming Zhou Wrote:
>>>> Now PSI already tracked workload pressure stall information for
>>>> CPU, memory and IO. Apart from these, IRQ/SOFTIRQ could have
>>>> obvious impact on some workload productivity, such as web service
>>>> workload.
>>>>
>>>> When CONFIG_IRQ_TIME_ACCOUNTING, we can get IRQ/SOFTIRQ delta time
>>>> from update_rq_clock_task(), in which we can record that delta
>>>> to CPU curr task's cgroups as PSI_IRQ_FULL status.
>>>
>>> The {soft,}irq affection should be equal to all the runnable tasks
>>> on that cpu, not only rq->curr. Further I think irqstall is per-cpu
>>> rather than per-cgroup.
>>
>> Although IRQ/SOFTIRQ is per-cpu, it's the rq->curr who own the CPU at the time
>> and pay for it, meanwhile other groups would be thought as PSI_CPU_FULL.
>
> I don't think rq->curr pays for it if you mean consuming quota here.
Yes, it makes rq->curr's groups look more productive than it actually is,
which are clearly different from other groups.
> And it doesn't seem appropriate to let other groups treat it as cpu
> stall because the rq->curr is also the victim rather than the one
> causes stall (so it's different from rq->curr causing memstall and
> observed as cpustall by others).
IMHO, we don't care who causes stall, instead we care about what affects
workload productivity.
>
>>
>> So I think it's reasonable to account this IRQ/SOFTIRQ delta to rq->curr's groups
>> as PSI_IRQ_FULL pressure stall. And per-cpu IRQ stall can also get from psi_system.
>>
>
next prev parent reply other threads:[~2022-07-22 7:33 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 4:04 [PATCH 0/9] sched/psi: some optimization and extension Chengming Zhou
2022-07-21 4:04 ` [PATCH 1/9] sched/psi: fix periodic aggregation shut off Chengming Zhou
2022-07-25 15:34 ` Johannes Weiner
2022-07-25 15:39 ` Johannes Weiner
2022-07-26 13:28 ` Chengming Zhou
2022-07-21 4:04 ` [PATCH 2/9] sched/psi: optimize task switch inside shared cgroups again Chengming Zhou
2022-07-21 4:04 ` [PATCH 3/9] sched/psi: move private helpers to sched/stats.h Chengming Zhou
2022-07-25 16:39 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 4/9] sched/psi: don't change task psi_flags when migrate CPU/group Chengming Zhou
2022-07-21 4:04 ` [PATCH 5/9] sched/psi: don't create cgroup PSI files when psi_disabled Chengming Zhou
2022-07-25 16:41 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 6/9] sched/psi: save percpu memory when !psi_cgroups_enabled Chengming Zhou
2022-07-25 16:47 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 7/9] sched/psi: cache parent psi_group to speed up groups iterate Chengming Zhou
2022-07-21 4:04 ` [PATCH 8/9] sched/psi: add kernel cmdline parameter psi_inner_cgroup Chengming Zhou
2022-07-25 16:52 ` Johannes Weiner
2022-07-26 13:38 ` [External] " Chengming Zhou
2022-07-26 17:54 ` Tejun Heo
2022-08-03 12:17 ` Chengming Zhou
2022-08-03 17:58 ` Tejun Heo
2022-08-03 19:22 ` Johannes Weiner
2022-08-03 19:48 ` Tejun Heo
2022-08-04 13:51 ` Chengming Zhou
2022-08-04 16:56 ` Johannes Weiner
2022-08-04 2:02 ` Chengming Zhou
2022-07-21 4:04 ` [PATCH 9/9] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure Chengming Zhou
2022-07-21 10:00 ` kernel test robot
2022-07-21 22:10 ` kernel test robot
2022-07-22 3:30 ` Abel Wu
2022-07-22 6:13 ` Chengming Zhou
2022-07-22 7:14 ` Abel Wu
2022-07-22 7:33 ` Chengming Zhou [this message]
2022-07-25 18:26 ` Johannes Weiner
2022-07-26 13:55 ` [External] " Chengming Zhou
2022-07-27 11:28 ` Chengming Zhou
2022-07-27 13:00 ` Johannes Weiner
2022-07-27 15:09 ` Chengming Zhou
2022-07-27 16:07 ` Peter Zijlstra
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=ab445d4d-70d2-9e6f-dd1d-9e71f00c1796@bytedance.com \
--to=zhouchengming@bytedance.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=corbet@lwn.net \
--cc=hannes@cmpxchg.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rdunlap@infradead.org \
--cc=songmuchun@bytedance.com \
--cc=surenb@google.com \
--cc=tj@kernel.org \
--cc=wuyun.abel@bytedance.com \
/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).