Re: [dpdk-dev] [PATCH v2] ethdev: warn once for buggy applications

[Thomas Monjalon <thomas@monjalon.net>]

> > Warning continuously is a pain when developping or if a unit test
> > is/gets broken.
> > 
> > It could also be a problem if application behaves badly only in some
> > corner cases and a DoS results of those logs being continuously displayed.
> > 
> > Let's warn once per port and per rx/tx.
> > 
> > Getting such a log is scary, but let's make it more eye catching by
> > dumping a backtrace with it.
> > 
> > Tested by introducing a bug in testpmd:
> >  static int
> >  eth_dev_start_mp(uint16_t port_id)
> >  {
> > -       if (is_proc_primary())
> > +       if (!is_proc_primary())
> >                 return rte_eth_dev_start(port_id);
> > 
> >         return 0;
> > 
> > Then, running a basic null test:
> > $ ./devtools/test-null.sh
> > ...
> > Start automatic packet forwarding
> > io packet forwarding - ports=2 - cores=1 - streams=2 - NUMA support
> >   enabled, MP allocation mode: native
> > Logical Core 1 (socket 0) forwards packets on 2 streams:
> >   RX P=0/Q=0 (socket 0) -> TX P=1/Q=0 (socket 0) peer=02:00:00:00:00:01
> >   RX P=1/Q=0 (socket 0) -> TX P=0/Q=0 (socket 0) peer=02:00:00:00:00:00
> > 
> > lcore 0 called rx_pkt_burst for not ready port 0
> > 8: [build/app/dpdk-testpmd() [0x59e839]]
> > 7: [/lib64/libc.so.6(__libc_start_main+0xf5) [0x7ff481b69555]]
> > 6: [build/app/dpdk-testpmd(main+0x54b) [0x662d24]]
> > 5: [build/app/dpdk-testpmd(start_packet_forwarding+0x263) [0x65e795]]
> > 4: [build/app/dpdk-testpmd() [0x65e1be]]
> > 3: [build/app/dpdk-testpmd() [0x65a996]]
> > 2: [build/app/dpdk-testpmd() [0xa6cbc7]]
> > 1: [build/app/dpdk-testpmd(rte_dump_stack+0x27) [0xaee796]]
> > lcore 0 called rx_pkt_burst for not ready port 1
> > 8: [build/app/dpdk-testpmd() [0x59e839]]
> > 7: [/lib64/libc.so.6(__libc_start_main+0xf5) [0x7ff481b69555]]
> > 6: [build/app/dpdk-testpmd(main+0x54b) [0x662d24]]
> > 5: [build/app/dpdk-testpmd(start_packet_forwarding+0x263) [0x65e795]]
> > 4: [build/app/dpdk-testpmd() [0x65e1be]]
> > 3: [build/app/dpdk-testpmd() [0x65a996]]
> > 2: [build/app/dpdk-testpmd() [0xa6cbc7]]
> > 1: [build/app/dpdk-testpmd(rte_dump_stack+0x27) [0xaee796]]
> >   io packet forwarding packets/burst=32
> >   nb forwarding cores=1 - nb forwarding ports=2
> >   port 0: RX queue number: 1 Tx queue number: 1
> >     Rx offloads=0x0 Tx offloads=0x0
> > 
> > Fixes: c87d435a4d79 ("ethdev: copy fast-path API into separate structure")
> > 
> > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > ---
> > Changes since v1:
> > - removed diff banner in commitlog,
> > - renamed vars,
> > - removed unneeded cast on anonymous struct in initialisation construct,
> > - added check on queue pointer,
> > 
> > ---
> 
> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Tested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

Acked-by: Thomas Monjalon <thomas@monjalon.net>