From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Tejun Heo <tj@kernel.org>
Cc: axboe@kernel.dk, baolin.wang7@gmail.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] blk-iocost: Optimize the ioc_refreash_vrate() function
Date: Fri, 4 Dec 2020 11:36:19 +0800 [thread overview]
Message-ID: <9d1098dc-f716-872b-ea63-aea4a44355dc@linux.alibaba.com> (raw)
In-Reply-To: <X8f5zQi+AzaY+ieY@mtj.duckdns.org>
在 2020/12/3 4:32, Tejun Heo 写道:
> On Sun, Nov 29, 2020 at 10:37:18AM +0800, Baolin Wang wrote:
>> The ioc_refreash_vrate() will only be called in ioc_timer_fn() after
>> starting a new period or stopping the period.
>>
>> So when starting a new period, the variable 'pleft' in ioc_refreash_vrate()
>> is always the period's time, which means if the abs(ioc->vtime_err)
>> is less than the period's time, the vcomp is 0, and we do not need
>> compensate the vtime_rate in this case, just set it as the base vrate
>> and return.
>>
>> When stopping the period, the ioc->vtime_err will be cleared to 0,
>> and we also do not need to compensate the vtime_rate, just set it as
>> the base vrate and return.
>
> Before, the function did something which is conceptually discrete and
> describable. After, its operation is intertwined with when it's called. I
> don't think this sort of micro optimizations are beneficial in cold paths.
OK. I understood your concern. Thanks for your input.
prev parent reply other threads:[~2020-12-04 3:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-29 2:37 [RFC PATCH] blk-iocost: Optimize the ioc_refreash_vrate() function Baolin Wang
2020-12-02 20:32 ` Tejun Heo
2020-12-04 3:36 ` Baolin Wang [this message]
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=9d1098dc-f716-872b-ea63-aea4a44355dc@linux.alibaba.com \
--to=baolin.wang@linux.alibaba.com \
--cc=axboe@kernel.dk \
--cc=baolin.wang7@gmail.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.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).