From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: kuniyu@google.com, ncardwell@google.com, netdev@vger.kernel.org,
davem@davemloft.net, pabeni@redhat.com, andrew+netdev@lunn.ch,
horms@kernel.org
Subject: Re: [PATCH net-next] tcp: try to defer / return acked skbs to originating CPU
Date: Mon, 19 Jan 2026 09:04:35 -0800 [thread overview]
Message-ID: <20260119090435.44b1da2d@kernel.org> (raw)
In-Reply-To: <CANn89iJ8+5OaWS2VzJqo4QVN6VY9zJvrJfP0TGRGv85mj09kjA@mail.gmail.com>
On Sun, 18 Jan 2026 13:15:00 +0100 Eric Dumazet wrote:
> > > Also, if workers are away from softirq, they will only process the
> > > defer queue in large patches, after receiving an trigger_rx_softirq()
> > > IPI.
> > > Any idea of skb_defer_free_flush() latency when dealing with batches
> > > of ~64 big TSO packets ?
> >
> > Not sure if there's much we can do about that.. Perhaps we should have
> > a shrinker that flushes the defer queues? I chatted with Shakeel briefly
> > and it sounded fairly straightforward.
>
> I was mostly concerned about latency spikes, I did some tests here and
> this seems fine.
Looks like selftests run into the zerocopy Tx latency issue.
I'll drop this version from patchwork..
> (I assume you asked Shakeel about the extra memory being held in the
> per-cpu queue, and pcp implications ?)
Under real load it helps quite a bit but real load flushes the queues
frequently. I'll talk to him.
next prev parent reply other threads:[~2026-01-19 17:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-17 16:42 [PATCH net-next] tcp: try to defer / return acked skbs to originating CPU Jakub Kicinski
2026-01-17 17:10 ` Jakub Kicinski
2026-01-17 18:16 ` Eric Dumazet
2026-01-17 23:03 ` Jakub Kicinski
2026-01-18 12:15 ` Eric Dumazet
2026-01-19 17:04 ` Jakub Kicinski [this message]
2026-01-29 23:04 ` Jakub Kicinski
2026-01-29 23:10 ` Jakub Kicinski
2026-02-16 16:06 ` Eric Dumazet
2026-02-16 17:49 ` Jakub Kicinski
2026-02-16 17:58 ` Eric Dumazet
2026-02-16 18:11 ` Jakub Kicinski
2026-02-16 18:16 ` Eric Dumazet
2026-02-17 21:50 ` Jakub Kicinski
2026-02-17 21:56 ` Eric Dumazet
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=20260119090435.44b1da2d@kernel.org \
--to=kuba@kernel.org \
--cc=andrew+netdev@lunn.ch \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=horms@kernel.org \
--cc=kuniyu@google.com \
--cc=ncardwell@google.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.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 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.