linux-kernel - Re: [PATCH v3] pipe: use __pipe_{lock,unlock} instead of spinlock

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Message-ID: <CA+icZUUdGCdzYvdi3_vdpHqNvE12wsAw3CKCmeut1-R78kjHHg@mail.gmail.com>
Date:   Fri, 6 Jan 2023 21:33:41 +0100
From:   Sedat Dilek <sedat.dilek@...il.com>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Hongchen Zhang <zhanghongchen@...ngson.cn>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Kuniyuki Iwashima <kuniyu@...zon.co.jp>,
        David Howells <dhowells@...hat.com>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Randy Dunlap <rdunlap@...radead.org>,
        Eric Dumazet <edumazet@...gle.com>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] pipe: use __pipe_{lock,unlock} instead of spinlock

On Fri, Jan 6, 2023 at 8:40 PM Luis Chamberlain <mcgrof@...nel.org> wrote:
>
> On Fri, Jan 06, 2023 at 05:48:44PM +0800, Hongchen Zhang wrote:
> > Use spinlock in pipe_read/write cost too much time,IMO
> > pipe->{head,tail} can be protected by __pipe_{lock,unlock}.
> > On the other hand, we can use __pipe_{lock,unlock} to protect
> > the pipe->{head,tail} in pipe_resize_ring and
> > post_one_notification.
> >
> > I tested this patch using UnixBench's pipe test case on a x86_64
> > machine,and get the following data:
> > 1) before this patch
> > System Benchmarks Partial Index  BASELINE       RESULT    INDEX
> > Pipe Throughput                   12440.0     493023.3    396.3
> >                                                         ========
> > System Benchmarks Index Score (Partial Only)              396.3
> >
> > 2) after this patch
> > System Benchmarks Partial Index  BASELINE       RESULT    INDEX
> > Pipe Throughput                   12440.0     507551.4    408.0
> >                                                         ========
> > System Benchmarks Index Score (Partial Only)              408.0
> >
> > so we get ~3% speedup.
> >
> > Signed-off-by: Hongchen Zhang <zhanghongchen@...ngson.cn>
> > ---
>
> After the above "---" line you should have the changlog descrption.
> For instance:
>
> v3:
>   - fixes bleh blah blah
> v2:
>   - fixes 0-day report by ... etc..
>   - fixes spelling or whatever
>
> I cannot decipher what you did here differently, not do I want to go
> looking and diff'ing. So you are making the life of reviewer harder.
>

Happy new 2023.

Positive wording... You can make reviewers' life easy when...
(encourage people).
Life is easy, people live hard.

+1 Adding ChangeLog of patch history

Cannot say...
Might be good to add the link to Linus test-case + your results in the
commit message as well?

...
Link: https://git.kernel.org/linus/0ddad21d3e99 (test-case of Linus
suggested-by Andrew)
...
Signed-off-by: Hongchen Zhang <zhanghongchen@...ngson.cn>
...

Thanks.

Best regards,
-Sedat-