Definition of the term rx/tx/combined channel

Definition of the term rx/tx/combined channel

[Amir Vadai]

Hi Ben,

I'm trying to understand the exact definition of the term channel.

According to ethtool: A channel is an IRQ and the set of queues that can
trigger that IRQ.

In our driver (Mellanox's Connect-X), we have an IRQ's, rx rings and tx
rings.

Usually we have one IRQ per rx ring, but if system resources are
limited, those numbers could be different.
tx rings are sharing the same IRQ's assigned by rx rings (for
completions), but many tx rings could share the same IRQ.

Is the rx channels == number of rx rings, and same for tx?
How is this related to the number of IRQ's?
Should we show other IRQ's we use for async events from the HW, as 'other'?

Thanks,
Amir

Re: Definition of the term rx/tx/combined channel

[Ben Hutchings]

On Sun, 2013-12-22 at 17:06 +0200, Amir Vadai wrote:
> Hi Ben,
> 
> I'm trying to understand the exact definition of the term channel.
> 
> According to ethtool: A channel is an IRQ and the set of queues that can
> trigger that IRQ.
> 
> In our driver (Mellanox's Connect-X), we have an IRQ's, rx rings and tx
> rings.
> 
> Usually we have one IRQ per rx ring, but if system resources are
> limited, those numbers could be different.
> tx rings are sharing the same IRQ's assigned by rx rings (for
> completions), but many tx rings could share the same IRQ.
> 
> Is the rx channels == number of rx rings, and same for tx?
> How is this related to the number of IRQ's?

If an IRQ is triggered by completions from both RX and TX rings then
that's a combined channel.

Do you want to make the number of TX rings per IRQ configurable through
ethtool?

> Should we show other IRQ's we use for async events from the HW, as 'other'?

If they are only used for those events and not also for completions,
then yes.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.