From: "yukuai (C)" <yukuai3@huawei.com>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <yi.zhang@huawei.com>
Subject: Re: [PATCH v2 2/4] block, bfq: do not idle if only one cgroup is activated
Date: Thu, 2 Sep 2021 21:31:26 +0800 [thread overview]
Message-ID: <da0e53b4-e947-9c91-832e-36da67037f0f@huawei.com> (raw)
In-Reply-To: <21FA636D-2C21-4ACD-B7DE-180ABB1F3562@linaro.org>
On 2021/08/27 1:00, Paolo Valente wrote:
>
> Why do you make these extensive changes, while you can leave all the
> function unchanged and just modify the above condition to something
> like
>
> || bfqd->num_groups_with_pending_reqs > 1
> || (bfqd->num_groups_with_pending_reqs && bfqd->num_queues_with_pending_reqs_in_root)
Hi, Paolo
I was thinking that if CONFIG_BFQ_GROUP_IOSCHED is enabled, there is no
need to caculate smallest_weight, varied_queue_weights, and
multiple_classes_busy:
If we count root group into num_groups_with_pending_reqs
- If num_groups_with_pending_reqs <= 1, idle is not needed
- If num_groups_with_pending_reqs > 1, idle is needed
Thus such changes can save some additional overhead.
Thanks
Yu Kuai
>
> In addition, I still wonder whether you can simply add also the root
> group to bfqd->num_groups_with_pending_reqs (when the root group is
> active). This would make the design much cleaner.
>
> Thanks,
> Paolo
>
>> -#endif
>> - ;
>> + return varied_queue_weights || multiple_classes_busy;
>> }
>>
>> /*
>> --
>> 2.31.1
>>
>
> .
>
next prev parent reply other threads:[~2021-09-02 13:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 2:08 [PATCH v2 0/4] optimize the bfq queue idle judgment Yu Kuai
2021-08-06 2:08 ` [PATCH v2 1/4] block, bfq: add support to track if root_group have any pending requests Yu Kuai
2021-08-26 17:00 ` Paolo Valente
2021-09-02 13:23 ` yukuai (C)
2021-08-06 2:08 ` [PATCH v2 2/4] block, bfq: do not idle if only one cgroup is activated Yu Kuai
2021-08-26 17:00 ` Paolo Valente
2021-09-02 13:31 ` yukuai (C) [this message]
2021-09-07 9:10 ` Paolo Valente
2021-09-07 11:19 ` yukuai (C)
2021-08-06 2:08 ` [PATCH v2 3/4] block, bfq: add support to record request size information Yu Kuai
2021-08-26 17:00 ` Paolo Valente
2021-08-06 2:08 ` [PATCH v2 4/4] block, bfq: consider request size in bfq_asymmetric_scenario() Yu Kuai
2021-08-26 17:00 ` Paolo Valente
2021-09-07 11:29 ` yukuai (C)
2021-09-15 7:36 ` Paolo Valente
2021-09-15 7:47 ` yukuai (C)
2021-08-14 2:34 ` [PATCH v2 0/4] optimize the bfq queue idle judgment yukuai (C)
2021-08-24 14:09 ` yukuai (C)
2021-08-26 16:59 ` Paolo Valente
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=da0e53b4-e947-9c91-832e-36da67037f0f@huawei.com \
--to=yukuai3@huawei.com \
--cc=axboe@kernel.dk \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paolo.valente@linaro.org \
--cc=yi.zhang@huawei.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).