Subject: Re: [net-next 08/15] net/mlx5e: Add hairpin debugfs files

From: Jakub Kicinski <[email-masked]>
Date: Tue, 17 Jan 2023 10:48:51 -0800

On Sun, 15 Jan 2023 12:04:58 +0200 Gal Pressman wrote:
> The hairpin queues are different than other queues in the driver as they
> are controlled by the device (refill, completion handling, etc.).
> Hardware configuration can make a difference in performance when working
> with hairpin, things that wouldn't necessarily affect regular queues the
> driver uses. The debugging process is also more difficult as the driver
> has little control/visibility over these.
> 
> At the end of the day, the debug process *is* going to be playing with
> the queue size/number, this allows us to potentially find a number that
> releases the bottleneck and see how it affects other stages in the pipe.
> Since these cases are unlikely to happen, and changing of these
> parameters can affect the device in other ways, we don't want people to
> just increase them when they encounter performance issues, especially
> not in production environments.
> 
> Does that make sense?

Okay, I think my guess that "debug" here means "wobble it to see if 
the device can go faster" was indeed correct. Long term maybe we should
find a better word for that than "debug".