[Intel-wired-lan] NAT performance issue 944mbit -> ~40mbit
Alexander Duyck
alexander.duyck at gmail.com
Wed Jul 15 22:32:45 UTC 2020
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.
> 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 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.
> 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.
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