[Intel-wired-lan] NAT performance issue 944mbit -> ~40mbit

Alexander Duyck alexander.duyck at gmail.com
Fri Jul 17 00:09:19 UTC 2020


On Thu, Jul 16, 2020 at 12:47 PM Ian Kumlien <ian.kumlien at gmail.com> wrote:
>
> Sorry, tried to respond via the phone, used the webbrowser version but
> still html mails... :/
>
> On Thu, Jul 16, 2020 at 5:18 PM Alexander Duyck
> <alexander.duyck at gmail.com> wrote:
> > On Wed, Jul 15, 2020 at 5:00 PM Ian Kumlien <ian.kumlien at gmail.com> wrote:
> > > On Thu, Jul 16, 2020 at 1:42 AM Alexander Duyck
> > > <alexander.duyck at gmail.com> wrote:
> > > > On Wed, Jul 15, 2020 at 3:51 PM Ian Kumlien <ian.kumlien at gmail.com> wrote:
> > > > > On Thu, Jul 16, 2020 at 12:32 AM Alexander Duyck
> > > > > <alexander.duyck at gmail.com> wrote:
> > > > > > On Wed, Jul 15, 2020 at 3:00 PM Ian Kumlien <ian.kumlien at gmail.com> wrote:
> > > > > > > On Wed, Jul 15, 2020 at 11:40 PM Jakub Kicinski <kuba at kernel.org> wrote:
> > > > > > > > On Wed, 15 Jul 2020 23:12:23 +0200 Ian Kumlien wrote:
> > > > > > > > > On Wed, Jul 15, 2020 at 11:02 PM Ian Kumlien <ian.kumlien at gmail.com> wrote:
> > > > > > > > > > On Wed, Jul 15, 2020 at 10:31 PM Jakub Kicinski <kuba at kernel.org> wrote:
> > > > > > > > > > > On Wed, 15 Jul 2020 22:05:58 +0200 Ian Kumlien wrote:
> > > > > > > > > > > > After a  lot of debugging it turns out that the bug is in igb...
> > > > > > > > > > > >
> > > > > > > > > > > > driver: igb
> > > > > > > > > > > > version: 5.6.0-k
> > > > > > > > > > > > firmware-version:  0. 6-1
> > > > > > > > > > > >
> > > > > > > > > > > > 03:00.0 Ethernet controller: Intel Corporation I211 Gigabit Network
> > > > > > > > > > > > Connection (rev 03)
> > > > > > > > > > >
> > > > > > > > > > > Unclear to me what you're actually reporting. Is this a regression
> > > > > > > > > > > after a kernel upgrade? Compared to no NAT?
> > > > > > > > > >
> > > > > > > > > > It only happens on "internet links"
> > > > > > > > > >
> > > > > > > > > > Lets say that A is client with ibg driver, B is a firewall running NAT
> > > > > > > > > > with ixgbe drivers, C is another local node with igb and
> > > > > > > > > > D is a remote node with a bridge backed by a bnx2 interface.
> > > > > > > > > >
> > > > > > > > > > A -> B -> C is ok (B and C is on the same switch)
> > > > > > > > > >
> > > > > > > > > > A -> B -> D -- 32-40mbit
> > > > > > > > > >
> > > > > > > > > > B -> D 944 mbit
> > > > > > > > > > C -> D 944 mbit
> > > > > > > > > >
> > > > > > > > > > A' -> D ~933 mbit (A with realtek nic -- also link is not idle atm)
> > > > > > > > >
> > > > > > > > > This should of course be A' -> B -> D
> > > > > > > > >
> > > > > > > > > Sorry, I've been scratching my head for about a week...
> > > > > > > >
> > > > > > > > Hm, only thing that comes to mind if A' works reliably and A doesn't is
> > > > > > > > that A has somehow broken TCP offloads. Could you try disabling things
> > > > > > > > via ethtool -K and see if those settings make a difference?
> > > > > > >
> > > > > > > It's a bit hard since it works like this, turned tso off:
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > > > [  5]   0.00-1.00   sec   108 MBytes   902 Mbits/sec    0    783 KBytes
> > > > > > > [  5]   1.00-2.00   sec   110 MBytes   923 Mbits/sec   31    812 KBytes
> > > > > > > [  5]   2.00-3.00   sec   111 MBytes   933 Mbits/sec   92    772 KBytes
> > > > > > > [  5]   3.00-4.00   sec   110 MBytes   923 Mbits/sec    0    834 KBytes
> > > > > > > [  5]   4.00-5.00   sec   111 MBytes   933 Mbits/sec   60    823 KBytes
> > > > > > > [  5]   5.00-6.00   sec   110 MBytes   923 Mbits/sec   31    789 KBytes
> > > > > > > [  5]   6.00-7.00   sec   111 MBytes   933 Mbits/sec    0    786 KBytes
> > > > > > > [  5]   7.00-8.00   sec   110 MBytes   923 Mbits/sec    0    761 KBytes
> > > > > > > [  5]   8.00-9.00   sec   110 MBytes   923 Mbits/sec    0    772 KBytes
> > > > > > > [  5]   9.00-10.00  sec   109 MBytes   912 Mbits/sec    0    868 KBytes
> > > > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > > > [  5]   0.00-10.00  sec  1.07 GBytes   923 Mbits/sec  214             sender
> > > > > > > [  5]   0.00-10.00  sec  1.07 GBytes   920 Mbits/sec                  receiver
> > > > > > >
> > > > > > > Continued running tests:
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > > > [  5]   0.00-1.00   sec  5.82 MBytes  48.8 Mbits/sec    0   82.0 KBytes
> > > > > > > [  5]   1.00-2.00   sec  4.97 MBytes  41.7 Mbits/sec    0    130 KBytes
> > > > > > > [  5]   2.00-3.00   sec  5.28 MBytes  44.3 Mbits/sec    0   99.0 KBytes
> > > > > > > [  5]   3.00-4.00   sec  5.28 MBytes  44.3 Mbits/sec    0    105 KBytes
> > > > > > > [  5]   4.00-5.00   sec  5.28 MBytes  44.3 Mbits/sec    0    122 KBytes
> > > > > > > [  5]   5.00-6.00   sec  5.28 MBytes  44.3 Mbits/sec    0   82.0 KBytes
> > > > > > > [  5]   6.00-7.00   sec  5.28 MBytes  44.3 Mbits/sec    0   79.2 KBytes
> > > > > > > [  5]   7.00-8.00   sec  5.28 MBytes  44.3 Mbits/sec    0    110 KBytes
> > > > > > > [  5]   8.00-9.00   sec  5.28 MBytes  44.3 Mbits/sec    0    156 KBytes
> > > > > > > [  5]   9.00-10.00  sec  5.28 MBytes  44.3 Mbits/sec    0   87.7 KBytes
> > > > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > > > [  5]   0.00-10.00  sec  53.0 MBytes  44.5 Mbits/sec    0             sender
> > > > > > > [  5]   0.00-10.00  sec  52.5 MBytes  44.1 Mbits/sec                  receiver
> > > > > > >
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > > > [  5]   0.00-1.00   sec  7.08 MBytes  59.4 Mbits/sec    0    156 KBytes
> > > > > > > [  5]   1.00-2.00   sec  5.97 MBytes  50.0 Mbits/sec    0    110 KBytes
> > > > > > > [  5]   2.00-3.00   sec  4.97 MBytes  41.7 Mbits/sec    0    124 KBytes
> > > > > > > [  5]   3.00-4.00   sec  5.47 MBytes  45.9 Mbits/sec    0   96.2 KBytes
> > > > > > > [  5]   4.00-5.00   sec  5.47 MBytes  45.9 Mbits/sec    0    158 KBytes
> > > > > > > [  5]   5.00-6.00   sec  4.97 MBytes  41.7 Mbits/sec    0   70.7 KBytes
> > > > > > > [  5]   6.00-7.00   sec  5.47 MBytes  45.9 Mbits/sec    0    113 KBytes
> > > > > > > [  5]   7.00-8.00   sec  5.47 MBytes  45.9 Mbits/sec    0   96.2 KBytes
> > > > > > > [  5]   8.00-9.00   sec  4.97 MBytes  41.7 Mbits/sec    0   84.8 KBytes
> > > > > > > [  5]   9.00-10.00  sec  5.47 MBytes  45.9 Mbits/sec    0    116 KBytes
> > > > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > > > [  5]   0.00-10.00  sec  55.3 MBytes  46.4 Mbits/sec    0             sender
> > > > > > > [  5]   0.00-10.00  sec  53.9 MBytes  45.2 Mbits/sec                  receiver
> > > > > > >
> > > > > > > And the low bandwidth continues with:
> > > > > > > ethtool -k enp3s0 |grep ": on"
> > > > > > > rx-vlan-offload: on
> > > > > > > tx-vlan-offload: on [requested off]
> > > > > > > highdma: on [fixed]
> > > > > > > rx-vlan-filter: on [fixed]
> > > > > > > tx-gre-segmentation: on
> > > > > > > tx-gre-csum-segmentation: on
> > > > > > > tx-ipxip4-segmentation: on
> > > > > > > tx-ipxip6-segmentation: on
> > > > > > > tx-udp_tnl-segmentation: on
> > > > > > > tx-udp_tnl-csum-segmentation: on
> > > > > > > tx-gso-partial: on
> > > > > > > tx-udp-segmentation: on
> > > > > > > hw-tc-offload: on
> > > > > > >
> > > > > > > Can't quite find how to turn those off since they aren't listed in
> > > > > > > ethtool (since the text is not what you use to enable/disable)
> > > > > >
> > > > > > To disable them you would just repeat the same string in the display
> > > > > > string. So it should just be "ethtool -K enp3s0 tx-gso-partial off"
> > > > > > and that would turn off a large chunk of them as all the encapsulated
> > > > > > support requires gso partial support.
> > > > >
> > > > >  ethtool -k enp3s0 |grep ": on"
> > > > > highdma: on [fixed]
> > > > > rx-vlan-filter: on [fixed]
> > > > > ---
> > > > > And then back to back:
> > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > [  5]   0.00-1.00   sec  4.91 MBytes  41.2 Mbits/sec    0   45.2 KBytes
> > > > > [  5]   1.00-2.00   sec  4.47 MBytes  37.5 Mbits/sec    0   52.3 KBytes
> > > > > [  5]   2.00-3.00   sec  4.47 MBytes  37.5 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   3.00-4.00   sec  4.47 MBytes  37.5 Mbits/sec    0    141 KBytes
> > > > > [  5]   4.00-5.00   sec   111 MBytes   928 Mbits/sec   63    764 KBytes
> > > > > [  5]   5.00-6.00   sec  86.2 MBytes   724 Mbits/sec    0    744 KBytes
> > > > > [  5]   6.00-7.00   sec  98.8 MBytes   828 Mbits/sec   61    769 KBytes
> > > > > [  5]   7.00-8.00   sec   110 MBytes   923 Mbits/sec    0    749 KBytes
> > > > > [  5]   8.00-9.00   sec   110 MBytes   923 Mbits/sec    0    741 KBytes
> > > > > [  5]   9.00-10.00  sec   110 MBytes   923 Mbits/sec   31    761 KBytes
> > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > [  5]   0.00-10.00  sec   644 MBytes   540 Mbits/sec  155             sender
> > > > > [  5]   0.00-10.01  sec   641 MBytes   537 Mbits/sec                  receiver
> > > > >
> > > > > and we're back at the not working bit:
> > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > [  5]   0.00-1.00   sec  4.84 MBytes  40.6 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   1.00-2.00   sec  4.60 MBytes  38.6 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   2.00-3.00   sec  4.23 MBytes  35.4 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   3.00-4.00   sec  4.47 MBytes  37.5 Mbits/sec    0   67.9 KBytes
> > > > > [  5]   4.00-5.00   sec  4.47 MBytes  37.5 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   5.00-6.00   sec  4.23 MBytes  35.4 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   6.00-7.00   sec  4.23 MBytes  35.4 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   7.00-8.00   sec  4.47 MBytes  37.5 Mbits/sec    0   67.9 KBytes
> > > > > [  5]   8.00-9.00   sec  4.47 MBytes  37.5 Mbits/sec    0   53.7 KBytes
> > > > > [  5]   9.00-10.00  sec  4.47 MBytes  37.5 Mbits/sec    0   79.2 KBytes
> > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > [  5]   0.00-10.00  sec  44.5 MBytes  37.3 Mbits/sec    0             sender
> > > > > [  5]   0.00-10.00  sec  43.9 MBytes  36.8 Mbits/sec                  receiver
> > > > >
> > > > > > > I was hoping that you'd have a clue of something that might introduce
> > > > > > > a regression - ie specific patches to try to revert
> > > > > > >
> > > > > > > Btw, the same issue applies to udp as werll
> > > > > > >
> > > > > > > [ ID] Interval           Transfer     Bitrate         Total Datagrams
> > > > > > > [  5]   0.00-1.00   sec  6.77 MBytes  56.8 Mbits/sec  4900
> > > > > > > [  5]   1.00-2.00   sec  4.27 MBytes  35.8 Mbits/sec  3089
> > > > > > > [  5]   2.00-3.00   sec  4.20 MBytes  35.2 Mbits/sec  3041
> > > > > > > [  5]   3.00-4.00   sec  4.30 MBytes  36.1 Mbits/sec  3116
> > > > > > > [  5]   4.00-5.00   sec  4.24 MBytes  35.6 Mbits/sec  3070
> > > > > > > [  5]   5.00-6.00   sec  4.21 MBytes  35.3 Mbits/sec  3047
> > > > > > > [  5]   6.00-7.00   sec  4.29 MBytes  36.0 Mbits/sec  3110
> > > > > > > [  5]   7.00-8.00   sec  4.28 MBytes  35.9 Mbits/sec  3097
> > > > > > > [  5]   8.00-9.00   sec  4.25 MBytes  35.6 Mbits/sec  3075
> > > > > > > [  5]   9.00-10.00  sec  4.20 MBytes  35.2 Mbits/sec  3039
> > > > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > > > [ ID] Interval           Transfer     Bitrate         Jitter
> > > > > > > Lost/Total Datagrams
> > > > > > > [  5]   0.00-10.00  sec  45.0 MBytes  37.7 Mbits/sec  0.000 ms
> > > > > > > 0/32584 (0%)  sender
> > > > > > > [  5]   0.00-10.00  sec  45.0 MBytes  37.7 Mbits/sec  0.037 ms
> > > > > > > 0/32573 (0%)  receiver
> > > > > > >
> > > > > > > vs:
> > > > > > >
> > > > > > > [ ID] Interval           Transfer     Bitrate         Total Datagrams
> > > > > > > [  5]   0.00-1.00   sec   114 MBytes   954 Mbits/sec  82342
> > > > > > > [  5]   1.00-2.00   sec   114 MBytes   955 Mbits/sec  82439
> > > > > > > [  5]   2.00-3.00   sec   114 MBytes   956 Mbits/sec  82507
> > > > > > > [  5]   3.00-4.00   sec   114 MBytes   955 Mbits/sec  82432
> > > > > > > [  5]   4.00-5.00   sec   114 MBytes   956 Mbits/sec  82535
> > > > > > > [  5]   5.00-6.00   sec   114 MBytes   953 Mbits/sec  82240
> > > > > > > [  5]   6.00-7.00   sec   114 MBytes   956 Mbits/sec  82512
> > > > > > > [  5]   7.00-8.00   sec   114 MBytes   956 Mbits/sec  82503
> > > > > > > [  5]   8.00-9.00   sec   114 MBytes   956 Mbits/sec  82532
> > > > > > > [  5]   9.00-10.00  sec   114 MBytes   956 Mbits/sec  82488
> > > > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > > > [ ID] Interval           Transfer     Bitrate         Jitter
> > > > > > > Lost/Total Datagrams
> > > > > > > [  5]   0.00-10.00  sec  1.11 GBytes   955 Mbits/sec  0.000 ms
> > > > > > > 0/824530 (0%)  sender
> > > > > > > [  5]   0.00-10.01  sec  1.11 GBytes   949 Mbits/sec  0.014 ms
> > > > > > > 4756/824530 (0.58%)  receiver
> > > > > >
> > > > > > The fact that it is impacting UDP seems odd. I wonder if we don't have
> > > > > > a qdisc somewhere that is misbehaving and throttling the Tx. Either
> > > > > > that or I wonder if we are getting spammed with flow control frames.
> > > > >
> > > > > it sometimes works, it looks like the cwindow just isn't increased -
> > > > > that's where i started...
> > > > >
> > > > > Example:
> > > > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > > > [  5]   0.00-1.00   sec  4.86 MBytes  40.8 Mbits/sec    0   50.9 KBytes
> > > > > [  5]   1.00-2.00   sec  4.66 MBytes  39.1 Mbits/sec    0   65.0 KBytes
> > > > > [  5]   2.00-3.00   sec  4.29 MBytes  36.0 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   3.00-4.00   sec  4.66 MBytes  39.1 Mbits/sec    0   42.4 KBytes
> > > > > [  5]   4.00-5.00   sec  23.1 MBytes   194 Mbits/sec    0   1.07 MBytes
> > > > > [  5]   5.00-6.00   sec   110 MBytes   923 Mbits/sec    0    761 KBytes
> > > > > [  5]   6.00-7.00   sec  98.8 MBytes   828 Mbits/sec   60    806 KBytes
> > > > > [  5]   7.00-8.00   sec  82.5 MBytes   692 Mbits/sec    0    812 KBytes
> > > > > [  5]   8.00-9.00   sec   110 MBytes   923 Mbits/sec   92    761 KBytes
> > > > > [  5]   9.00-10.00  sec   111 MBytes   933 Mbits/sec    0    755 KBytes
> > > > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > > > [ ID] Interval           Transfer     Bitrate         Retr
> > > > > [  5]   0.00-10.00  sec   554 MBytes   465 Mbits/sec  152             sender
> > > > > [  5]   0.00-10.00  sec   550 MBytes   461 Mbits/sec                  receiver
> > > > >
> > > > > > It would be useful to include the output of just calling "ethtool
> > > > > > enp3s0" on the interface to verify the speed, "ethtool -a enp3s0" to
> > > > > > verify flow control settings, and "ethtool -S enp3s0 | grep -v :\ 0"
> > > > > > to output the statistics and dump anything that isn't zero.
> > > > >
> > > > > ethtool enp3s0
> > > > > Settings for enp3s0:
> > > > > Supported ports: [ TP ]
> > > > > Supported link modes:   10baseT/Half 10baseT/Full
> > > > >                         100baseT/Half 100baseT/Full
> > > > >                         1000baseT/Full
> > > > > Supported pause frame use: Symmetric
> > > > > Supports auto-negotiation: Yes
> > > > > Supported FEC modes: Not reported
> > > > > Advertised link modes:  10baseT/Half 10baseT/Full
> > > > >                         100baseT/Half 100baseT/Full
> > > > >                         1000baseT/Full
> > > > > Advertised pause frame use: Symmetric
> > > > > Advertised auto-negotiation: Yes
> > > > > Advertised FEC modes: Not reported
> > > > > Speed: 1000Mb/s
> > > > > Duplex: Full
> > > > > Auto-negotiation: on
> > > > > Port: Twisted Pair
> > > > > PHYAD: 1
> > > > > Transceiver: internal
> > > > > MDI-X: off (auto)
> > > > > Supports Wake-on: pumbg
> > > > > Wake-on: g
> > > > >         Current message level: 0x00000007 (7)
> > > > >                                drv probe link
> > > > > Link detected: yes
> > > > > ---
> > > > > ethtool -a enp3s0
> > > > > Pause parameters for enp3s0:
> > > > > Autonegotiate: on
> > > > > RX: on
> > > > > TX: off
> > > > > ---
> > > > > ethtool -S enp3s0 |grep  -v :\ 0
> > > > > NIC statistics:
> > > > >      rx_packets: 15920618
> > > > >      tx_packets: 17846725
> > > > >      rx_bytes: 15676264423
> > > > >      tx_bytes: 19925010639
> > > > >      rx_broadcast: 119553
> > > > >      tx_broadcast: 497
> > > > >      rx_multicast: 330193
> > > > >      tx_multicast: 18190
> > > > >      multicast: 330193
> > > > >      rx_missed_errors: 270102
> > > > >      rx_long_length_errors: 6
> > > > >      tx_tcp_seg_good: 1342561
> > > > >      rx_long_byte_count: 15676264423
> > > > >      rx_errors: 6
> > > > >      rx_length_errors: 6
> > > > >      rx_fifo_errors: 270102
> > > > >      tx_queue_0_packets: 7651168
> > > > >      tx_queue_0_bytes: 7823281566
> > > > >      tx_queue_0_restart: 4920
> > > > >      tx_queue_1_packets: 10195557
> > > > >      tx_queue_1_bytes: 12027522118
> > > > >      tx_queue_1_restart: 12718
> > > > >      rx_queue_0_packets: 15920618
> > > > >      rx_queue_0_bytes: 15612581951
> > > > >      rx_queue_0_csum_err: 76
> > > > > (I've only run two runs since i reenabled the interface)
> > > >
> > > > So I am seeing three things here.
> > > >
> > > > The rx_long_length_errors are usually due to an MTU mismatch. Do you
> > > > have something on the network that is using jumbo frames, or is the
> > > > MTU on the NIC set to something smaller than what is supported on the
> > > > network?
> > >
> > > I'm using jumbo frames on the local network, internet side is the
> > > normal 1500 bytes mtu though
> > >
> > > > You are getting rx_missed_errors, that would seem to imply that the
> > > > DMA is not able to keep up. We may want to try disabling the L1 to see
> > > > if we get any boost from doing that.
> > >
> > > It used to work, I don't do benchmarks all the time and sometimes the first
> > > benchmarks turn out fine... so it's hard to say when this started happening...
> > >
> > > It could also be related to a bios upgrade, but I'm pretty sure I did
> > > successful benchmarks after that...
> > >
> > > How do I disable the l1? just echo 0 >
> > > /sys/bus/pci/drivers/igb/0000\:03\:00.0/link/l1_aspm ?
> > >
> > > > The last bit is that queue 0 is seeing packets with bad checksums. You
> > > > might want to run some tests and see where the bad checksums are
> > > > coming from. If they are being detected from a specific NIC such as
> > > > the ixgbe in your example it might point to some sort of checksum
> > > > error being created as a result of the NAT translation.
> > >
> > > But that should also affect A' and the A -> B -> C case, which it doesn't...
> > >
> > > It only seems to happen with higher rtt (6 hops, sub 3 ms in this case
> > > but still high enough somehow)
> > >
> > > > > ---
> > > > >
> > > > > > > lspci -s 03:00.0  -vvv
> > > > > > > 03:00.0 Ethernet controller: Intel Corporation I211 Gigabit Network
> > > > > > > Connection (rev 03)
> > > > > > > Subsystem: ASUSTeK Computer Inc. I211 Gigabit Network Connection
> > > > > > > Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
> > > > > > > Stepping- SERR- FastB2B- DisINTx+
> > > > > > > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
> > > > > > > <TAbort- <MAbort- >SERR- <PERR- INTx-
> > > > > > > Latency: 0
> > > > > > > Interrupt: pin A routed to IRQ 57
> > > > > > > IOMMU group: 20
> > > > > > > Region 0: Memory at fc900000 (32-bit, non-prefetchable) [size=128K]
> > > > > > > Region 2: I/O ports at e000 [size=32]
> > > > > > > Region 3: Memory at fc920000 (32-bit, non-prefetchable) [size=16K]
> > > > > > > Capabilities: [40] Power Management version 3
> > > > > > > Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
> > > > > > > Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=1 PME-
> > > > > > > Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
> > > > > > > Address: 0000000000000000  Data: 0000
> > > > > > > Masking: 00000000  Pending: 00000000
> > > > > > > Capabilities: [70] MSI-X: Enable+ Count=5 Masked-
> > > > > > > Vector table: BAR=3 offset=00000000
> > > > > > > PBA: BAR=3 offset=00002000
> > > > > > > Capabilities: [a0] Express (v2) Endpoint, MSI 00
> > > > > > > DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
> > > > > > > ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
> > > > > > > DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+
> > > > > > > RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
> > > > > > > MaxPayload 128 bytes, MaxReadReq 512 bytes
> > > > > > > DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
> > > > > > > LnkCap: Port #3, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency
> > > > > > > L0s <2us, L1 <16us
> > > > > > > ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
> > > > > > > LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
> > > > > > > ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> > > > > > > LnkSta: Speed 2.5GT/s (ok), Width x1 (ok)
> > > > > > > TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
> > > > > >
> > > > > > PCIe wise the connection is going to be pretty tight in terms of
> > > > > > bandwidth. It looks like we have 2.5GT/s with only a single lane of
> > > > > > PCIe. In addition we are running with ASPM enabled so that means that
> > > > > > if we don't have enough traffic we are shutting off the one PCIe lane
> > > > > > we have so if we are getting bursty traffic that can get ugly.
> > > > >
> > > > > Humm... is there a way to force disable ASPM in sysfs?
> > > >
> > > > Actually the easiest way to do this is to just use setpci.
> > > >
> > > > You should be able to dump the word containing the setting via:
> > > > # setpci -s 3:00.0 0xB0.w
> > > > 0042
> > > > # setpci -s 3:00.0 0xB0.w=0040
> > > >
> > > > Basically what you do is clear the lower 3 bits of the value so in
> > > > this case that means replacing the 2 with a 0 based on the output of
> > > > the first command.
> > >
> > > Well... I'll be damned... I used to force enable ASPM... this must be
> > > related to the change in PCIe bus ASPM
> > > Perhaps disable ASPM if there is only one link?
> >
> > Is there any specific reason why you are enabling ASPM? Is this system
> > a laptop where you are trying to conserve power when on battery? If
> > not disabling it probably won't hurt things too much since the power
> > consumption for a 2.5GT/s link operating in a width of one shouldn't
> > bee too high. Otherwise you are likely going to end up paying the
> > price for getting the interface out of L1 when the traffic goes idle
> > so you are going to see flows that get bursty paying a heavy penalty
> > when they start dropping packets.
>
> Ah, you misunderstand, I used to do this and everything worked - now
> Linux enables ASPM by default on all pcie controllers,
> so imho this should be a quirk, if there is only one lane, don't do
> ASPM due to latency and timing issues...
>
> > It is also possible this could be something that changed with the
> > physical PCIe link. Basically L1 works by powering down the link when
> > idle, and then powering it back up when there is activity. The problem
> > is bringing it back up can sometimes be a challenge when the physical
> > link starts to go faulty. I know I have seen that in some cases it can
> > even result in the device falling off of the PCIe bus if the link
> > training fails.
>
> It works fine without ASPM (and the machine is pretty new)
>
> I suspect we hit some timing race with aggressive ASPM (assumed as
> such since it works on local links but doesn't on ~3 ms Links)

Agreed. What is probably happening if you are using a NAT is that it
may be seeing some burstiness being introduced and as a result the
part is going to sleep and then being overrun when the traffic does
arrive.

> > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > [  5]   0.00-1.00   sec   113 MBytes   950 Mbits/sec   31    710 KBytes
> > > [  5]   1.00-2.00   sec   110 MBytes   923 Mbits/sec  135    626 KBytes
> > > [  5]   2.00-3.00   sec   112 MBytes   944 Mbits/sec   18    713 KBytes
> > > [  5]   3.00-4.00   sec   111 MBytes   933 Mbits/sec    0    798 KBytes
> > > [  5]   4.00-5.00   sec   111 MBytes   933 Mbits/sec    0    721 KBytes
> > > [  5]   5.00-6.00   sec   112 MBytes   944 Mbits/sec   31    800 KBytes
> > > [  5]   6.00-7.00   sec   111 MBytes   933 Mbits/sec    0    730 KBytes
> > > [  5]   7.00-8.00   sec   111 MBytes   933 Mbits/sec   19    730 KBytes
> > > [  5]   8.00-9.00   sec   111 MBytes   933 Mbits/sec    0    701 KBytes
> > > [  5]   9.00-10.00  sec   112 MBytes   944 Mbits/sec   12    701 KBytes
> > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > [ ID] Interval           Transfer     Bitrate         Retr
> > > [  5]   0.00-10.00  sec  1.09 GBytes   937 Mbits/sec  246             sender
> > > [  5]   0.00-10.01  sec  1.09 GBytes   933 Mbits/sec                  receiver
> > >
> > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > [  5]   0.00-1.00   sec   114 MBytes   956 Mbits/sec    0    749 KBytes
> > > [  5]   1.00-2.00   sec   111 MBytes   933 Mbits/sec   30    766 KBytes
> > > [  5]   2.00-3.00   sec   112 MBytes   944 Mbits/sec    7    749 KBytes
> > > [  5]   3.00-4.00   sec   111 MBytes   933 Mbits/sec   11    707 KBytes
> > > [  5]   4.00-5.00   sec   111 MBytes   933 Mbits/sec    2    699 KBytes
> > > [  5]   5.00-6.00   sec   111 MBytes   933 Mbits/sec    8    699 KBytes
> > > [  5]   6.00-7.00   sec   112 MBytes   944 Mbits/sec    1    953 KBytes
> > > [  5]   7.00-8.00   sec   111 MBytes   933 Mbits/sec    0    701 KBytes
> > > [  5]   8.00-9.00   sec   111 MBytes   933 Mbits/sec   26    707 KBytes
> > > [  5]   9.00-10.00  sec   112 MBytes   944 Mbits/sec    2   1.07 MBytes
> > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > [ ID] Interval           Transfer     Bitrate         Retr
> > > [  5]   0.00-10.00  sec  1.09 GBytes   939 Mbits/sec   87             sender
> > > [  5]   0.00-10.00  sec  1.09 GBytes   934 Mbits/sec                  receiver
> > >
> > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > [  5]   0.00-1.00   sec   114 MBytes   953 Mbits/sec   16    908 KBytes
> > > [  5]   1.00-2.00   sec   112 MBytes   944 Mbits/sec    0    693 KBytes
> > > [  5]   2.00-3.00   sec   111 MBytes   933 Mbits/sec    0    713 KBytes
> > > [  5]   3.00-4.00   sec   111 MBytes   933 Mbits/sec    0    687 KBytes
> > > [  5]   4.00-5.00   sec   112 MBytes   944 Mbits/sec   15    687 KBytes
> > > [  5]   5.00-6.00   sec   111 MBytes   933 Mbits/sec    2    888 KBytes
> > > [  5]   6.00-7.00   sec   111 MBytes   933 Mbits/sec   17    696 KBytes
> > > [  5]   7.00-8.00   sec   111 MBytes   933 Mbits/sec    0    758 KBytes
> > > [  5]   8.00-9.00   sec   111 MBytes   933 Mbits/sec   31    749 KBytes
> > > [  5]   9.00-10.00  sec   112 MBytes   944 Mbits/sec    0    792 KBytes
> > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > [ ID] Interval           Transfer     Bitrate         Retr
> > > [  5]   0.00-10.00  sec  1.09 GBytes   938 Mbits/sec   81             sender
> > > [  5]   0.00-10.00  sec  1.09 GBytes   934 Mbits/sec                  receiver
> > >
> > > [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
> > > [  5]   0.00-1.00   sec   114 MBytes   956 Mbits/sec    0    747 KBytes
> > > [  5]   1.00-2.00   sec   111 MBytes   933 Mbits/sec    0    744 KBytes
> > > [  5]   2.00-3.00   sec   112 MBytes   944 Mbits/sec   12   1.18 MBytes
> > > [  5]   3.00-4.00   sec   111 MBytes   933 Mbits/sec    2    699 KBytes
> > > [  5]   4.00-5.00   sec   111 MBytes   933 Mbits/sec   28    699 KBytes
> > > [  5]   5.00-6.00   sec   112 MBytes   944 Mbits/sec    0    684 KBytes
> > > [  5]   6.00-7.00   sec   111 MBytes   933 Mbits/sec    0    741 KBytes
> > > [  5]   7.00-8.00   sec   111 MBytes   933 Mbits/sec    3    687 KBytes
> > > [  5]   8.00-9.00   sec   111 MBytes   933 Mbits/sec   22    699 KBytes
> > > [  5]   9.00-10.00  sec   111 MBytes   933 Mbits/sec   11    707 KBytes
> > > - - - - - - - - - - - - - - - - - - - - - - - - -
> > > [ ID] Interval           Transfer     Bitrate         Retr
> > > [  5]   0.00-10.00  sec  1.09 GBytes   938 Mbits/sec   78             sender
> > > [  5]   0.00-10.01  sec  1.09 GBytes   934 Mbits/sec                  receiver
> > > ---
> > >
> > > ethtool -S enp3s0 |grep -v ": 0"
> > > NIC statistics:
> > >      rx_packets: 16303520
> > >      tx_packets: 21602840
> > >      rx_bytes: 15711958157
> > >      tx_bytes: 25599009212
> > >      rx_broadcast: 122212
> > >      tx_broadcast: 530
> > >      rx_multicast: 333489
> > >      tx_multicast: 18446
> > >      multicast: 333489
> > >      rx_missed_errors: 270143
> > >      rx_long_length_errors: 6
> > >      tx_tcp_seg_good: 1342561
> > >      rx_long_byte_count: 15711958157
> > >      rx_errors: 6
> > >      rx_length_errors: 6
> > >      rx_fifo_errors: 270143
> > >      tx_queue_0_packets: 8963830
> > >      tx_queue_0_bytes: 9803196683
> > >      tx_queue_0_restart: 4920
> > >      tx_queue_1_packets: 12639010
> > >      tx_queue_1_bytes: 15706576814
> > >      tx_queue_1_restart: 12718
> > >      rx_queue_0_packets: 16303520
> > >      rx_queue_0_bytes: 15646744077
> > >      rx_queue_0_csum_err: 76
> >
> > Okay, so this result still has the same length and checksum errors,
> > were you resetting the system/statistics between runs?
>
> Ah, no.... Will reset and do more tests when I'm back home
>
> Am I blind or is this part missing from ethtools man page?

There isn't a reset that will reset the stats via ethtool. The device
stats will be persistent until the driver is unloaded and reloaded or
the system is reset. You can reset the queue stats by changing the
number of queues. So for example using "ethtool -L enp3s0 1;  ethtool
-L enp3s0 2".


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