Re: [PATCH net-next 0/4] net/smc: Add SMC statistic support

[Guvenc Gulce <guvenc@linux.ibm.com>]

Hi Dave,
Thank you for looking into this. SMC is a protocol interacting with PCI devices (like RoCE Cards) and
runs on top of TCP protocol. As SMC is a network protocol and not an ethernet device driver, we
decided to use the generic netlink interface. There is already an established internal generic netlink
interface mechanism in SMC which is used to collect SMC Protocol internal information. This patchset
extends that existing mechanism.
Ethtool's predefined netlink interfaces are specifically tailored for the ethernet device internals and needs
and these netlink interfaces wouldn't really fit to the use cases of the SMC protocol.

Other protocols (like tipc, ncsi, ieee802154, tcp metrics) under the net subsystem use also similar generic
netlink mechanism for collecting and transporting protocol specific information to userspace. This also
encouraged us to make the generic netlink decision for exposing the gathered SMC protocol statistics
and internal information to the userspace.

Regards,

Guvenc Gulce

On 07/06/2021 22:33, David Miller wrote:
> From: Karsten Graul <kgraul@linux.ibm.com>
> Date: Mon,  7 Jun 2021 20:20:10 +0200
>
>> Please apply the following patch series for smc to netdev's net-next tree.
>>
>> The patchset adds statistic support to the SMC protocol. Per-cpu
>> variables are used to collect the statistic information for better
>> performance and for reducing concurrency pitfalls. The code that is
>> collecting statistic data is implemented in macros to increase code
>> reuse and readability.
>> The generic netlink mechanism in SMC is extended to provide the
>> collected statistics to userspace.
>> Network namespace awareness is also part of the statistics
>> implementation.
> Why not use ethtool stats?
>
> Thank you.