Re: [Linuxptp-users] Intel NICs PTP Performance Comparison

[Joseph M. <jos...@gm...>]

Just editing the comparison table:

#        NIC        # Driver   #   Version   #       FW-Version     #
Test-Results
=======================================================
# Intel I210      # igb        # 5.4.0-k       # 3.25, 0x80000678 # GOOD
# Intel 82574L # e1000e # 3.2.6-k       # 1.8-0                     # GOOD
# Intel I218-V  # e1000e # 3.2.6-k        # 0.2-4                     # BAD
# Intel I218-V  # e1000e # 3.8.7-NAPI # 0.2-4                     # BAD
# Intel I219-V  # e1000e # 3.2.6-k        # 0.4-4                     # BAD




On Thu, Jun 17, 2021 at 5:14 PM Joseph Matan <jos...@gm...>
wrote:

> Hi experts,
>
> I'm working with different NIC devices, and I've seen that some of them
> don't have a "good" PTP performance (later I'll describe what I define as
> "good").
> I decided to run a short test, and write a comparison table.
> I believe that maybe some of you are familiar with the behaviour I've
> encountered.
>
> The NICs unders test are (all Intel): I210, 82574L, I218-V, I219-V.
> My setup is as described below:
>
> [NIC under test / MASTER] <---- [2 meter cable] ----> [KSZ9477 / SLAVE]
>
> The Slave is always KSZ9477.
>
> Only the Master is replaced between each test.
>
> There is only a cable between Master and Slave. No other devices or
> switches.
>
>
> Both master and slave support HW timestamping.
>
> NIC Driver Version FW-Version Test Results
> Intel I210 igb 5.4.0-k 3.25, 0x80000678 GOOD
> Intel 82574L e1000e 3.2.6-k 1.8-0 GOOD
> Intel I218-V e1000e 3.2.6-k 0.2-4 BAD
> Intel I218-V e1000e 3.8.7-NAPI 0.2-4 BAD
> Intel I219-V e1000e 3.2.6-k 0.4-4 BAD
>
> Test results description:
>
> GOOD:
>
> Delay is always around 20 nsec (10 nsec jitter), even under heavy traffic.
>
> Offset is always < 200 nsec, even under heavy traffic.
>
> BAD:
>
> Unstable delay.
>
> With no traffic, the delay is around 7500-8000 nsec.
>
> Under heavy traffic it gets smaller - reaching a delay of 800 nsec and
> stabilizes on 800 nsec.
>
> When traffic goes off, delay reaches back to 7500-8000 nsec.
>
> Offset can jitter up to 5000 nsec, but it stabilizes when the delay is
> stabilized.
>
> The interesting thing I saw in the I218/I219 is that after a while of
> traffic (1 or 2 minutes), the delay is stabilized on 800 nsec,
> and when I turn off the traffic, the delay is still left stabilized on 800
> nsec for a ~15 seconds, and only then starts go back to its original value
> of 7500-8000 nesc (and same behaviour vice versa).
> I must say it looks more like a feature than a bug (that maybe I just need
> to disable).
> I thought maybe: EEE, Low Power Mode or Flow Control (I tried disabling
> them with ethtool, but results didn't change - maybe using ethtool is not
> the right way to do that...)
>
> Does anyone is familiar with such a behaviour with Intel I218/I219 ?
>
> Thanks,
> Joseph
>