Hi Vinicius,
On 5/19/20 7:37 PM, Vinicius Costa Gomes wrote:
Andre Guedes <andre.gue...@intel.com> writes:
Hi,
Quoting Vinicius Costa Gomes (2020-05-15 18:29:44)
One example, for retrieving and setting the configuration:
$ ethtool $ sudo ./ethtool --show-frame-preemption enp3s0
Frame preemption settings for enp3s0:
support: supported
active: active
IIUC the code in patch 2, 'active' is the actual configuration knob that
enables or disables the FP functionality on the NIC.
That sounded a bit confusing to me since the spec uses the term 'active' to
indicate FP is currently enabled at both ends, and it is a read-only
information (see 12.30.1.4 from IEEE 802.1Q-2018). Maybe if we called this
'enabled' it would be more clear.
Good point. Will rename this to "enabled".
supported queues: 0xf
supported queues: 0xe
minimum fragment size: 68
I'm assuming this is the configuration knob for the minimal non-final fragment
defined in 802.3br.
My understanding from the specs is that this value must be a multiple from 64
and cannot assume arbitrary values like shown here. See 99.4.7.3 from IEEE
802.3 and Note 1 in S.2 from IEEE 802.1Q. In the previous discussion about FP,
we had this as a multiplier factor, not absolute value.
I thought that exposing this as "(1 + N)*64" (with 0 <= N <= 3) that it
was more related to what's exposed via LLDP than the actual capabilities
of the hardware. And for the hardware I have actually the values
supported are: (1 + N)*64 + 4 (for N = 0, 1, 2, 3).
So I thought I was better to let the driver decide what values are
acceptable.
This is a good question for people working with other hardware.
AM65 CPSW supports this as a multiple of 64. Since this ethtool
configuration is for the hardware, might want to make it as a multiple
of 64.
Murali
--
Murali Karicheri
Texas Instruments
