TX vs RX pause frame question

TX vs RX pause frame question

[Benjamin Herrenschmidt]

Hi !

It's not 100% clear to me looking at various drivers what is
considered "rx_pause" and what is "tx_pause" (from the ethtool
terminology).

Is "rx_pause" about receiving pause frame to throttle the transmitter
or is it about sending pause frames when the receiver gets full ?

Thanks,
Ben.

Re: TX vs RX pause frame question

[John Fastabend]

On 17-03-26 03:11 AM, Benjamin Herrenschmidt wrote:
> Hi !
> 
> It's not 100% clear to me looking at various drivers what is
> considered "rx_pause" and what is "tx_pause" (from the ethtool
> terminology).
> 
> Is "rx_pause" about receiving pause frame to throttle the transmitter
> or is it about sending pause frames when the receiver gets full ?
> 
> Thanks,
> Ben.
> 

The common implementation, at least on the Intel devices, is rx_pause
should be enabled so the device will respond to receiving a pause frame, e.g.
stop sending packets. And tx_pause is for enabling/disabling sending of
pause frames.

Thanks,
John

Re: TX vs RX pause frame question

[Benjamin Herrenschmidt]

On Sun, 2017-03-26 at 10:55 -0700, John Fastabend wrote:
> On 17-03-26 03:11 AM, Benjamin Herrenschmidt wrote:
> > Hi !
> > 
> > It's not 100% clear to me looking at various drivers what is
> > considered "rx_pause" and what is "tx_pause" (from the ethtool
> > terminology).
> > 
> > Is "rx_pause" about receiving pause frame to throttle the transmitter
> > or is it about sending pause frames when the receiver gets full ?
> > 
> > Thanks,
> > Ben.
> > 
> 
> The common implementation, at least on the Intel devices, is rx_pause
> should be enabled so the device will respond to receiving a pause frame, e.g.
> stop sending packets. And tx_pause is for enabling/disabling sending of
> pause frames.

Thanks, I'll have my driver match that.

Cheers,
Ben.