Re: [PATCH 08/14] tap: Remove unhelpeful vnet_pre optimization from tap_send()

On Tue, Oct 18, 2022 at 05:05:13AM +0200, Stefano Brivio wrote:

On Mon, 17 Oct 2022 19:58:01 +1100 David Gibson wrote:

...

Callers of tap_send() can optionally use a small optimization by adding extra space for the 4 byte length header used on the qemu socket interface. tap_ip_send() is currently the only user of this, but this is used only for "slow path" ICMP and DHCP packets, so there's not a lot of value to the optimization.

Not anymore, definitely. It used to look quite bad in perf(1) when I shuffled connection data around.

Yeah. In any case I think I can get an equivalent optimization back at some point. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson