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Date: Fri, 3 Jul 2026 16:13:49 +0200
From: Brett Sheffield <bacs@librecast.net>
To: "Michael S. Tsirkin" <mst@redhat.com>
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
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In-Reply-To: <20260702185420-mutt-send-email-mst@kernel.org>

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.


-- 
Brett Sheffield (he/him)
Librecast - Decentralising the Internet with Multicast
https://librecast.net/
https://blog.brettsheffield.com/