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

Ian Kumlien ian.kumlien at gmail.com
Wed Jul 15 22:51:04 UTC 2020


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)
---

> > 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?


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