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Message-ID: <5528D4F0.6060203@broadcom.com>
Date: Sat, 11 Apr 2015 01:01:52 -0700
From: Prashant <prashant@...adcom.com>
To: Ian Jackson <Ian.Jackson@...citrix.com>
CC: Michael Chan <mchan@...adcom.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
David Vrabel <david.vrabel@...rix.com>,
Thadeu Lima de Souza Cascardo <cascardo@...ux.vnet.ibm.com>,
Vlad Yasevich <vyasevich@...il.com>,
<xen-devel@...ts.xensource.com>, <netdev@...r.kernel.org>
Subject: Re: tg3 NIC driver bug in 3.14.x under Xen [and 3 more messages]
On 4/10/2015 8:06 AM, Ian Jackson wrote:
> (I switched to a different test box "elbling1" with the same symptoms:
> ~25% packet loss in ping under 64-bit Xen with 32-bit x86 Linux; 100%
> loss Linux x86 32-bit baremetal with `iommu=soft swiotlb=force'. In
> each case I had disabled the bridge setup so was just using eth0.)
>
> Once again, tcpdumping eth0 with machine booted baremetal with the
> `iommu...' boot options shows corrupted packets on the receive path:
>
> Full transcript below. The non-corrupted packets (ARP requests) in
> the tcpdump are outgoing: 172.16.144.31 is elbling1.
>
> I think the packets are being dropped by the non-tg3 part of the
> kernel due to their protocol field having been corrupted.
> Also:
>
> root@...ling1:~# ethtool -S eth0 | grep -v ': 0$'
> NIC statistics:
> rx_octets: 352487
> rx_ucast_packets: 250
> rx_mcast_packets: 1165
> rx_bcast_packets: 1806
> tx_octets: 15848
> tx_mcast_packets: 8
> tx_bcast_packets: 237
> root@...ling1:~# ifconfig eth0
> eth0 Link encap:Ethernet HWaddr b0:83:fe:db:b6:69
> inet addr:172.16.144.31 Bcast:172.16.147.255
> Mask:255.255.252.0
> inet6 addr: fe80::b283:feff:fedb:b669/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3245 errors:0 dropped:223 overruns:0 frame:0
> TX packets:245 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:355364 (347.0 KiB) TX bytes:15848 (15.4 KiB)
> Interrupt:16
>
> root@...ling1:~#
>
Thanks for the detailed info, looking at the logs it appears sometimes
the descriptor itself is corrupted(drop count going up due to error bits
getting set in the descriptor) and some instances the RX data buffer is
getting corrupted (as seen in the tcpdump).
I tried to reproduce the problem on 32 bit 3.14.34 stable kernel
baremetal, with iommu=soft swiotlb=force but no luck, no drops or
errors. I did not try with Xen 64 bit yet. Btw I need a pcie analyzer
trace to confirm the problem. Is it feasible to capture at your end ?
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