From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: stable@dpdk.org, Reshma Pattan <reshma.pattan@intel.com>
Subject: Re: [PATCH 1/2] pcapng: revert use of reciprocal divide for timestamps
Date: Tue, 29 Sep 2026 08:36:08 -0700 [thread overview]
Message-ID: <20260929083608.1da61ca9@phoenix.local> (raw)
In-Reply-To: <20260927195015.78109-1-stephen@networkplumber.org>
On Sun, 27 Sep 2026 12:50:14 -0700
Stephen Hemminger <stephen@networkplumber.org> wrote:
> The use of recprocal divide caused in calculating timestamps
> caused overflow wraparound. This bug was introduced by confusion
> about bits, shift, and the test was too short to catch the
> problem.
>
> Go back to just doing the divide which ends up faster on many
> than having to do 128 bit math on many CPU types.
>
> This is not a pure git revert because there were other
> good things in that commit like handling earlier packets,
> and catching if TSC hz was zero.
>
> Fixes: 4fc65615b274 ("pcapng: improve performance of timestamping")
> Cc: stable@dpdk.org
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
Both applied to next-net
prev parent reply other threads:[~2026-09-29 15:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-27 19:50 [PATCH 1/2] pcapng: revert use of reciprocal divide for timestamps Stephen Hemminger
2026-09-27 19:50 ` [PATCH 2/2] test/pcapng: check timestamps over a long capture Stephen Hemminger
2026-09-29 15:36 ` Stephen Hemminger [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=20260929083608.1da61ca9@phoenix.local \
--to=stephen@networkplumber.org \
--cc=dev@dpdk.org \
--cc=reshma.pattan@intel.com \
--cc=stable@dpdk.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.