Re: [dpdk-dev] [PATCH v4 0/2] ethdev: add port speed capability bitmap

["Morten Brørup" <mb@smartsharesystems.com>]

Adrien Mazarguil [mailto:adrien.mazarguil@6wind.com] on 15. september 2015 12:05:

> A given link cannot be simultaneously at 10 Gbps and 1 Gbps right? Using a bit-field for the current link speed is confusing at best. Output values do not need to be included in the unified API, they are never converted back into enum values.

A given link can only use one speed at any given time, correct. However, other link properties must be output too, such as link status, duplex status, auto negotiation status, flow control status, media status, etc..  Using a bitfield provides all this information in an atomic operation.

> I'm stressing again the fact that doing so would require a changes in all applications that use the current speed and in PMDs for no good reason.

Correct, it requires a lot of changes in all the PMDs. I think a good PHY API with the appropriate features is a good reason. If there is no consensus to put in the work to update the PHY API and PMDs accordingly, just leave it at its former state.


I recently saw an interesting presentation about TCP optimization, and the last slide has a very good point. It says (slightly paraphrased): "You can't sell just the traffic handling, you need the support infrastructure for O&M, such as CLI, Web UI, Historical counter database, SNMP, RADIUS, Analytics and so on." So related to our PHY API discussion, I would add that proper handling of the physical interfaces is one of those things that just need to be in order when you sell network appliances.


Med venlig hilsen / kind regards
- Morten Brørup