Re: Testpmd/l3fwd port shutdown failure on Arm Altra systems

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

Hello i40e and testpmd maintainers,

A gentle reminder - would you please advise how to debug the issue
described below?

Thanks,
Juraj

On Fri, Jan 20, 2023 at 1:07 PM Juraj Linkeš <juraj.linkes@pantheon.tech> wrote:
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> Adding the logfile.
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> One thing that's in the logs but didn't explicitly mention is the DPDK version we've tried this with:
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> EAL: RTE Version: 'DPDK 22.07.0'
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> We also tried earlier versions going back to 21.08, with no luck. I also did a quick check on 22.11, also with no luck.
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> Juraj
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> From: Juraj Linkeš
> Sent: Friday, January 20, 2023 12:56 PM
> To: 'aman.deep.singh@intel.com' <aman.deep.singh@intel.com>; 'yuying.zhang@intel.com' <yuying.zhang@intel.com>; Xing, Beilei <beilei.xing@intel.com>
> Cc: dev@dpdk.org; Ruifeng Wang <Ruifeng.Wang@arm.com>; 'Lijian Zhang' <Lijian.Zhang@arm.com>; 'Honnappa Nagarahalli' <Honnappa.Nagarahalli@arm.com>
> Subject: Testpmd/l3fwd port shutdown failure on Arm Altra systems
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> Hello i40e and testpmd maintainers,
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> We're hitting an issue with DPDK testpmd on Ampere Altra servers in FD.io lab.
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> A bit of background: along with VPP performance tests (which uses DPDK), we're running a small number of basic DPDK testpmd and l3fwd tests in FD.io as well. This is to catch any performance differences due to VPP updating its DPDK version.
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> We're running both l3fwd tests and testpmd tests. The Altra servers are two socket and the topology is TG -> DUT1 -> DUT2 -> TG, traffic flows in both directions, but nothing gets forwarded (with a slight caveat - put a pin in this). There's nothing special in the tests, just forwarding traffic. The NIC we're testing is xl710-QDA2.
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> The same tests are passing on all other testbeds - we have various two node (1 DUT, 1 TG) and three node (2 DUT, 1 TG) Intel and Arm testbeds and with various NICs (Intel 700 and 800 series and the Intel testbeds use some Mellanox NICs as well). We don't have quite the same combination of another three node topology with the same NIC though, so it looks like something with testpmd/l3fwd and xl710-QDA2 on Altra servers.
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> VPP performance tests are passing, but l3fwd and testpmd fail. This leads us to believe to it's a software issue, but there could something wrong with the hardware. I'll talk about testpmd from now on, but as far we can tell, the behavior is the same for testpmd and l3fwd.
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> Getting back to the caveat mentioned earlier, there seems to be something wrong with port shutdown. When running testpmd on a testbed that hasn't been used for a while it seems that all ports are up right away (we don't see any "Port 0|1: link state change event") and the setup works fine (forwarding works). After restarting testpmd (restarting on one server is sufficient), the ports between DUT1 and DUT2 (but not between DUTs and TG) go down and are not usable in DPDK, VPP or in Linux (with i40e kernel driver) for a while (measured in minutes, sometimes dozens of minutes; the duration is seemingly random). The ports eventually recover and can be used again, but there's nothing in syslog suggesting what happened.
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> What seems to be happening is testpmd put the ports into some faulty state. This only happens on the DUT1 -> DUT2 link though (the ports between the two testpmds), not on TG -> DUT1 link (the TG port is left alone).
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> Some more info:
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> We've come across the issue with this configuration:
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> OS: Ubuntu20.04 with kernel 5.4.0-65-generic.
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> Old NIC firmware, never upgraded: 6.01 0x800035da 1.1747.0.
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> Drivers versions: i40e 2.17.15 and iavf 4.3.19.
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> As well as with this configuration:
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> OS: Ubuntu22.04 with kernel 5.15.0-46-generic.
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> Updated firmware: 8.30 0x8000a4ae 1.2926.0.
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> Drivers: i40e 2.19.3 and iavf 4.5.3.
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> Unsafe noiommu mode is disabled:
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> cat /sys/module/vfio/parameters/enable_unsafe_noiommu_mode
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> N
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> We used DPDK 22.07 in manual testing and built it on DUTs, using generic build:
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> meson -Dexamples=l3fwd -Dc_args=-DRTE_LIBRTE_I40E_16BYTE_RX_DESC=y -Dplatform=generic build
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> We're running testpmd with this command:
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> sudo build/app/dpdk-testpmd -v -l 1,2 -a 0004:04:00.1 -a 0004:04:00.0 --in-memory -- -i --forward-mode=io --burst=64 --txq=1 --rxq=1 --tx-offloads=0x0 --numa --auto-start --total-num-mbufs=32768 --nb-ports=2 --portmask=0x3 --max-pkt-len=1518 --mbuf-size=16384 --nb-cores=1
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> And l3fwd (with different macs on the other server):
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> sudo /tmp/openvpp-testing/dpdk/build/examples/dpdk-l3fwd -v -l 1,2 -a 0004:04:00.0 -a 0004:04:00.1 --in-memory -- --parse-ptype --eth-dest="0,40:a6:b7:85:e7:79" --eth-dest="1,3c:fd:fe:c3:e7:a1" --config="(0, 0, 2),(1, 0, 2)" -P -L -p 0x3
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> We tried adding logs with  --log-level=pmd,debug and --no-lsc-interrupt, but that didn't reveal anything helpful, as far as we can tell - please have a look at the attached log. The faulty port is port0 (starts out as down, then we waited for around 25 minutes for it to go up and then we shut down testpmd).
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> We'd like to ask for pointers on what could be the cause or how to debug this issue further.
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> Thanks,
> Juraj