On Sat, 10 Apr 2021 15:34:46 +0200 Ansuel Smith <ansuels...@gmail.com> wrote:
> Hi, > this is a respin of the Marek series in hope that this time we can > finally make some progress with dsa supporting multi-cpu port. > > This implementation is similar to the Marek series but with some tweaks. > This adds support for multiple-cpu port but leave the driver the > decision of the type of logic to use about assigning a CPU port to the > various port. The driver can also provide no preference and the CPU port > is decided using a round-robin way. In the last couple of months I have been giving some thought to this problem, and came up with one important thing: if there are multiple upstream ports, it would make a lot of sense to dynamically reallocate them to each user port, based on which user port is actually used, and at what speed. For example on Turris Omnia we have 2 CPU ports and 5 user ports. All ports support at most 1 Gbps. Round-robin would assign: CPU port 0 - Port 0 CPU port 1 - Port 1 CPU port 0 - Port 2 CPU port 1 - Port 3 CPU port 0 - Port 4 Now suppose that the user plugs ethernet cables only into ports 0 and 2, with 1, 3 and 4 free: CPU port 0 - Port 0 (plugged) CPU port 1 - Port 1 (free) CPU port 0 - Port 2 (plugged) CPU port 1 - Port 3 (free) CPU port 0 - Port 4 (free) We end up in a situation where ports 0 and 2 share 1 Gbps bandwidth to CPU, and the second CPU port is not used at all. A mechanism for automatic reassignment of CPU ports would be ideal here. What do you guys think? Marek
