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 <joseph.matan...@gmail.com> 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 >
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