Hi Stephen, Ferruh, As an end-user take on this (hence community comment) :), this ties into the rte_eth_tap that Keith sent out and it has been acked and reviewed, So I am trying to see the pros/cons of using this (kni pmd) vs. the tun/tap PMD [1].
Previously, we were using Ferruh's KDP/KCP patches and those served our purpose, but since the KDP/KCP idea has been rejected as yet another set of out-of-tree kernel modules to maintain, it has not gotten much attention since then. We are hoping that tun/tap would be the way to go just because it looks simple and easy to manage from a user app perspective. Having said that, I am not sure what to make of this KNI PMD given Stephen's comments. Could any one comment about the overall direction of which solution to focus on? (tun/tap PMD or KNI pmd)? [1]: http://dpdk.org/dev/patchwork/patch/16566/ (Keith's tun/tap PMD) Thanks. Aws\ On Fri, Oct 28, 2016 at 12:25 PM, Stephen Hemminger < stephen at networkplumber.org> wrote: > On Fri, 28 Oct 2016 15:31:50 +0100 > Ferruh Yigit <ferruh.yigit at intel.com> wrote: > > > Discussed alternatives were: > > * Tun/Tap > > This won't be as fast as KNI and performance is an issue. > > > That is a myth. Both require the some number of copies. > TUN/TAP copies is a syscall and KNI copies is a kthread. > Actually, the KNI method is worse because it has kernel thread > always running chewing a CPU. I.e it is pure poll mode. >
