From: "Michael S. Tsirkin" <mst@redhat.com>
To: Brett Sheffield <bacs@librecast.net>
Cc: Simon Schippers <simon.schippers@tu-dortmund.de>,
regressions@lists.linux.dev, netdev@vger.kernel.org,
Jakub Kicinski <kuba@kernel.org>,
Tim Gebauer <tim.gebauer@tu-dortmund.de>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Jason Wang <jasowang@redhat.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [REGRESSION][BISECTED] tun/tap & vhost-net: multi-threaded network performance
Date: Fri, 3 Jul 2026 10:19:40 -0400 [thread overview]
Message-ID: <20260703101823-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <akfDnfkgorxJ_Q6G@karahi.librecast.net>
On Fri, Jul 03, 2026 at 04:13:49PM +0200, Brett Sheffield wrote:
> On 2026-07-02 18:55, Michael S. Tsirkin wrote:
> > On Thu, Jul 02, 2026 at 01:07:47PM +0200, Brett Sheffield wrote:
> > > On 2026-07-02 09:24, Simon Schippers wrote:
> > > > On 7/1/26 22:56, Michael S. Tsirkin wrote:
> > > > > - does it help to increase the tun queue size?
> > > >
> > > > I agree, this would be great to know.
>
> I tried adding a queue (qdisc pfifo limit 500) on both host and guest - no
> apparent difference in drops or performance.
>
> If there's any other setting you want me to try, let me know.
>
> > Maybe it's the supposedly rare case? Does this change anything
> > for you?
>
> I also tried both patches, but again, no noticable difference.
>
Thank you. Simon pointed out issues with the patches but he also said his
intuition is strongly that it's not the way to go.
Let's wait for him to post the backpressure patch, we'll see.
--
MST
next prev parent reply other threads:[~2026-07-03 14:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 19:16 [REGRESSION][BISECTED] tun/tap & vhost-net: multi-threaded network performance Brett Sheffield
2026-07-01 20:56 ` Michael S. Tsirkin
2026-07-02 7:24 ` Simon Schippers
2026-07-02 7:42 ` Michael S. Tsirkin
2026-07-02 8:01 ` Simon Schippers
2026-07-02 11:07 ` Brett Sheffield
2026-07-02 22:44 ` Michael S. Tsirkin
2026-07-03 10:34 ` Simon Schippers
2026-07-02 22:55 ` Michael S. Tsirkin
2026-07-03 10:35 ` Simon Schippers
2026-07-03 14:13 ` Brett Sheffield
2026-07-03 14:19 ` Michael S. Tsirkin [this message]
2026-07-03 10:41 ` Simon Schippers
2026-07-03 11:55 ` Michael S. Tsirkin
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