Re: [net-next 4/8] net/mlx5e: Add device out of buffer counter

From: Saeed Mahameed <saeedm@mellanox.com>
To: "jakub.kicinski@netronome.com" <jakub.kicinski@netronome.com>
Cc: "davem@davemloft.net" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Moshe Shemesh <moshe@mellanox.com>
Subject: Re: [net-next 4/8] net/mlx5e: Add device out of buffer counter
Date: Mon, 26 Aug 2019 23:06:53 +0000	[thread overview]
Message-ID: <3be3a78c989e86f6761d3c0a66d6b24d50d1da8e.camel@mellanox.com> (raw)
In-Reply-To: <20190826133949.0691660c@cakuba.netronome.com>

On Mon, 2019-08-26 at 13:39 -0700, Jakub Kicinski wrote:
> On Mon, 26 Aug 2019 20:14:47 +0000, Saeed Mahameed wrote:
> > > I see thanks for the explanation and sorry for the delayed
> > > response.
> > > Would it perhaps make sense to indicate the hairpin in the
> > > name?  
> > 
> > We had some internal discussion and we couldn't come up with the
> > perfect name :)
> > 
> > hairpin is just an implementation detail, we don't want to
> > exclusively
> > bind this counter to hairpin only flows, the problem is not with
> > hairpin, the actual problem is due to the use of internal RQs, for
> > now
> > it only happens with "hairpin like" flows, but tomorrow it can
> > happen
> > with a different scenario but same root cause (the use of internal
> > RQs), we want to have one counter to count internal drops due to
> > internal use of internal RQs.
> > 
> > so how about:
> > dev_internal_rq_oob: Device Internal RQ out of buffer
> > dev_internal_out_of_res: Device Internal out of resources (more
> > generic
> > ? too generic ?)
> 
> Maybe dev_internal_queue_oob? The use of 'internal' is a little
> unfortunate, because it may be read as RQ run out of internal
> buffers.
> Rather than special type of queue run out of buffers.
> But not knowing the HW I don't really have any great suggestions :(
> Either of the above would work as well.
> 

True, even our HW architects didn't know how to call it, since sticking
to a name now that might be deprecated in a future HW is what we are
trying to avoid. a generic name is preferable.

I like dev_internal_queue_oob, will take it with the team and send v2tomorrow. 

thanks Jakub for the support.

> > Any suggestion that you provide will be more than welcome.
> > 
> > > dev_out_of_buffer is quite a generic name, and there seems to be
> > > no
> > > doc, nor does the commit message explains it as well as you
> > > have..  
> > 
> > Regarding documentation:
> > All mlx5 ethool counters are documented here
> > https://community.mellanox.com/s/article/understanding-mlx5-linux-counters-and-status-parameters
> > 
> > once we decide on the name, will add the new counter to the doc.
> 
> I see, thanks!

I will add a link to this file in 
https://www.kernel.org/doc/html/latest/networking/device_drivers/mellanox/mlx5.html?highlight=mlx5