From: Stephen Hemminger <stephen@networkplumber.org>
To: Ferruh Yigit <ferruh.yigit@amd.com>
Cc: dev@dpdk.org, "John W. Linville" <linville@tuxdriver.com>,
"Mattias Rönnblom" <hofors@lysator.liu.se>
Subject: Re: [PATCH] net/af_packet: fix statistics
Date: Wed, 1 May 2024 09:43:03 -0700 [thread overview]
Message-ID: <20240501094303.751e95b4@hermes.local> (raw)
In-Reply-To: <9025199c-585c-4779-9f4e-360845707088@amd.com>
On Wed, 1 May 2024 17:25:59 +0100
Ferruh Yigit <ferruh.yigit@amd.com> wrote:
> > - Do not mark statistics as volatile.
> > Instead, READ_ONCE() where necessary.
> >
>
> I did similar [1], and Mattias has some comments on it.
> Issue is not in the reader (stats_get) side. Without volatile writer
> (datapath thread) may end up *not* storing updated stats to memory.
>
> For reader side, I expect value not been in the register when function
> called, so it ends up reading from memory, which doesn't require
> volatile casting.
These are per-queue stats, and anybody foolish enough to have multiple
threads sharing same queue without locking is playing with fire.
It is documented that DPDK PMD's don't support that.
next prev parent reply other threads:[~2024-05-01 16:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-30 15:39 Stephen Hemminger
2024-05-01 16:25 ` Ferruh Yigit
2024-05-01 16:42 ` Stephen Hemminger
2024-05-02 13:48 ` Ferruh Yigit
2024-05-01 16:43 ` Stephen Hemminger [this message]
2024-05-02 14:12 ` Ferruh Yigit
2024-05-02 16:16 ` Stephen Hemminger
2024-05-02 17:57 ` Mattias Rönnblom
2024-05-01 16:44 ` Stephen Hemminger
2024-05-01 18:18 ` Morten Brørup
2024-05-02 13:47 ` Ferruh Yigit
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=20240501094303.751e95b4@hermes.local \
--to=stephen@networkplumber.org \
--cc=dev@dpdk.org \
--cc=ferruh.yigit@amd.com \
--cc=hofors@lysator.liu.se \
--cc=linville@tuxdriver.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).