On 11/26/25 08:15, Michael S. Tsirkin wrote:
> On Fri, Nov 21, 2025 at 10:22:54AM +0100, Simon Schippers wrote:
>> I agree, but I really would like to reduce the buffer bloat caused by the
>> default 500 TUN / 1000 TAP packet queue without losing performance.
> 
> that default is part of the userspace API and can't be changed.
> just change whatever userspace is creating your device.
> 

Yes, but I’m thinking about introducing a new interface flag like
IFF_BQL. However, as noted earlier, there are significant implementation
challenges.

I think there can be advantages to something like VPN's on mobile
devices where the throughput varies between a few Mbit/s (small TUN/TAP
queue is fine) and multiple Gbit/s (need a bigger queue).