[ovs-discuss] Starting OVS w/ DPDK ...

Mon Sep 17 18:25:43 UTC 2018

On Thu, Sep 13, 2018 at 04:56:51PM +0200, Andrzej Ostruszka wrote:
> First of all, thank you for your reply Flavio.
> 
> On 12.09.2018 19:33, Flavio Leitner wrote:
> > On Wed, Sep 12, 2018 at 09:21:18AM +0200, Andrzej Ostruszka wrote:
> [...]
> >> but when I try to start the vswitchd I'm getting errors:
> >>
> >> # ovs-ctl --no-ovsdb-server start
> > 
> > I don't know which OVS version is this and it may be because ovs-ctl
> > is trying to load the module or because ovs-vswitchd is doing that.
> > So, running sh -x ovs-ctl ... might shed a bit of light.
> 
> The version is 2.9.2 (build from git tag v2.9.2 with the previously
> mentioned configure line).
> 
> This is the ovs-ctl that is unconditionally trying to load modules.
> 
> start -> start_ovsdb & start_forwarding
> start_forwarding -> do_start_forwarding -> insert_mod_if_required

Yeah, the initialization scripts doesn't know what is in the db, so
it seems convenient to just load the module.

> and "if_required" part of that function only skips loading if module is
> already present or there is no support in kernel for modules.  Below are
> some snippets from "sh -x
> /usr/local/ovs/share/openvswitch/scripts/ovs-ctl --no-ovsdb-server start"
[...]
> modprobe: ERROR: could not insert 'openvswitch': Unknown symbol in
> module, or unknown parameter (see d
> mesg)

You can work around that in modprobe.conf, e.g.:
install openvswitch /bin/true

> I'm not sure why openvswitch module is needed in case of using DPDK
> based ports.  That might be just the case of documentation not being up
> to date (in case it is needed) or missing checks in ovs-ctl (in case it
> can be skipped for DPDK based switching).

I suspect it is the latter.

> Anyway I've decided to reconfigure my kernel to match requirements of
> openvswitch module (some config options were missing) and now I have
> some progress (I load Marvell's modules, configure huge pages first,
> then I start db and set dpd-init to true - as previously):
> 
> # ovs-ctl --no-ovsdb-server start
>  * Starting ovs-vswitchd
> 
>  * Enabling remote OVSDB managers
> 
> # ovs-ctl status
> ovsdb-server is running with pid 2928
> 
> ovs-vswitchd is running with pid 3055
> 
> # ovs-vsctl show
> 78e4732f-e2e1-4784-971c-f4d67e163a26
> 
>     Bridge "br0"
> 
>         Port "br0"
> 
>             Interface "br0"
> 
>                 type: internal
> 
>     ovs_version: "2.9.2"
> 
> 
> so it looks like I'm good to go but I get problems when I try to add
> ports to it.

BTW the bridge 'br0' also needs to be in the userspace DP.

> # ovs-vsctl add-port br0 port0 -- set Interface port0 type=dpdk
> options:dpdk-devargs=eth_mvpp20,iface=eth0 ofport_request=1
> 
> [ 7156.926062] pgd = ffffffc23465a000
> 
> [ 7156.927215] pgd = ffffffc23465a000
> 
> [ 7156.927278] [00000008] *pgd=0000000235346003, *pud=0000000235346003,
> *pmd=0000000000000000
> [ 7156.941365] [00000000] *pgd=0000000235346003, *pud=0000000235346003,
> *pmd=0000000000000000
> [ 7161.622915] pgd = ffffffc1ddd54000
> 
> [ 7161.622938] [00000008] *pgd=00000001ddd55003, *pud=00000001ddd55003,
> *pmd=0000000000000000
> 
> and I don't get command prompt again unless I interrupt with ^C.
> I have no idea what ofport_request=1 is for - I'm just copying from the
> docs (I assume this just gives id to port).  This type of log is

The ofport_request tells the switch that you want a specific OpenFlow
port ID for that port. If you don't provide it, then the vswitch will
get the next available to you.

> periodic - ovs-vswitchd seems to be crashing and is being periodically
> restarted.  In dmesg I see periodic entries as in [1] and in
> var/run/openvswitch I get ovs-vswitchd.PID.ctl sockets being added.
> 
> So I infer that for some reason vswitchd is crashing and I'd like to
> investigate that.  Any tips on how could I proceed with it?

Look at ovs-vswitchd.log and possibly the core dump file.

OVS can start the monitoring threads, then if the vswitchd crashes, it
will try to bring it up again.  There are some safe guards there to
avoid loops.

> Best regards
> Andrzej
> 
> [1] example of dmesg entry:
> --8<----------------

I'd say to stop trying with OVS and try ``testpmd´´ from DPDK directly and
see if you can get it working. It is the simplest possible scenario
where you can tell that at least the bare bones are working.

> [10262.208121] CMA: total alloc 314, total free: 314 (garbage 1)
> [10271.717382] CMA buffer allocated: size = 41943040 Bytes, kvaddr =
> ffffffc1de5f6000, paddr = 0xb050
> 0000
> [10271.717458] CMA buffer remapped: vm_start=0x7f3c800000, size =
> 41943040 bytes, paddr = 0xb0500000
> [10271.893887] pmd8[6947]: unhandled level 2 translation fault (11) at
> 0x00000000, esr 0x92000006
> [10271.893893] pgd = ffffffc1de506000
> [10271.893957] [6936]: unhandled level 2 translation fault (11) at
> 0x00000008, esr 0x92000006
> [10271.893958] pgd = ffffffc1de506000
> [10271.893962] [00000008] *pgd=00000001dde36003, *pud=00000001dde36003,
> *pmd=0000000000000000
> 
> [10271.893966] CPU: 1 PID: 6936 Comm:  Tainted: G           O
> 4.4.52-armada-17.10.4-g2dfc733 #2
> [10271.893967] Hardware name: Marvell Armada-8040 development board
> default (A) setup (DT)
> [10271.893968] task: ffffffc234609700 ti: ffffffc2345e8000 task.ti:
> ffffffc2345e8000
> [10271.893970] PC is at 0x86ba68
> [10271.893971] LR is at 0x5f03d0
> [10271.893973] pc : [<000000000086ba68>] lr : [<00000000005f03d0>]
> pstate: 80000000
> [10271.893974] sp : 0000007fd2d09aa0
> [10271.893976] x29: 0000007fd2d09aa0 x28: 000000000d971688
> [10271.893978] x27: 000000000d971660 x26: 000000000d898590
> [10271.893980] x25: 000000000d9d2820 x24: 000000000d8c4370
> [10271.893982] x23: 0000000000000000 x22: 0000000000000000
> [10271.893983] x21: 0000000000000000 x20: 000000000000000d
> [10271.893985] x19: 000000000d9d2910 x18: 0000000000000014
> [10271.893987] x17: 0000007f88100340 x16: 00000000009f8580
> [10271.893989] x15: ffffffffffffffff x14: ffff000000000000
> [10271.893991] x13: ffffffffffffffff x12: 0000000000000030
> [10271.893993] x11: 0000000000000004 x10: 0000007fd2d09bb0
> [10271.893994] x9 : 0000000000000004 x8 : 000000000d9d29e0
> [10271.893996] x7 : ffffffffffffffff x6 : 000000000000003f
> [10271.893998] x5 : 00000000000001d1 x4 : 0000000000000000
> [10271.894000] x3 : 00000000005f03a0 x2 : 0000000000000000
> [10271.894001] x1 : 0000007fd2d09ba8 x0 : 0000007fd2d09b38
> --8<----------------
> 
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-- 
Flavio