From: Simon Horman <horms@kernel.org>
To: Yu-Chun Lin <eleanor15x@gmail.com>
Cc: shshaikh@marvell.com, manishc@marvell.com,
GR-Linux-NIC-Dev@marvell.com, andrew+netdev@lunn.ch,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, jserv@ccns.ncku.edu.tw,
visitorckw@gmail.com
Subject: Re: [PATCH net-next] qlcnic: Optimize performance by replacing rw_lock with spinlock
Date: Fri, 7 Mar 2025 13:29:29 +0000 [thread overview]
Message-ID: <20250307132929.GI3666230@kernel.org> (raw)
In-Reply-To: <20250306163124.127473-1-eleanor15x@gmail.com>
On Fri, Mar 07, 2025 at 12:31:24AM +0800, Yu-Chun Lin wrote:
> The 'crb_lock', an rwlock, is only used by writers, making it functionally
> equivalent to a spinlock.
>
> According to Documentation/locking/spinlocks.rst:
>
> "Reader-writer locks require more atomic memory operations than simple
> spinlocks. Unless the reader critical section is long, you are better
> off just using spinlocks."
>
> Since read_lock() is never called, switching to a spinlock reduces
> overhead and improves efficiency.
>
> Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Hi Yu-Chun Lin,
Thanks for your patch.
My main question is if you have hardware to test this?
And if so, was a benefit observed?
If not, my feeling is that although your change looks
correct, we'd be better off taking the lower risk option
of leaving things be.
next prev parent reply other threads:[~2025-03-07 13:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-06 16:31 [PATCH net-next] qlcnic: Optimize performance by replacing rw_lock with spinlock Yu-Chun Lin
2025-03-07 13:29 ` Simon Horman [this message]
2025-03-08 16:35 ` Yu-Chun Lin
2025-03-11 11:15 ` Simon Horman
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=20250307132929.GI3666230@kernel.org \
--to=horms@kernel.org \
--cc=GR-Linux-NIC-Dev@marvell.com \
--cc=andrew+netdev@lunn.ch \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=eleanor15x@gmail.com \
--cc=jserv@ccns.ncku.edu.tw \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=manishc@marvell.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=shshaikh@marvell.com \
--cc=visitorckw@gmail.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).