lkml.org 
[lkml]   [2012]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: many rx packets dropped since 2.6.37
    From
    2012/4/25 Eric Dumazet <eric.dumazet@gmail.com>:
    > On Wed, 2012-04-25 at 16:38 +0200, Chris wrote:
    >> 2012/4/25 Eric Dumazet <eric.dumazet@gmail.com>:
    >> >> Why do we see dropped packets only in virtual environments and bonded
    >> >> network interfaces and not on real network interfaces?
    >> >
    >> > This has to be investigated, eventually.
    >>
    >> Do you have the opportunity to test it? Just install fedora 16 (linux
    >> 3.3) or ubuntu 12.04 (linux 3.2) as guest under kvm and use as virtual
    >> network card virtio_net or e1000.
    >>
    >> You will see many lost rx packets and i have no idea why???
    >
    >
    > You can use drop_monitor / dropwatch to figure out
    >
    > https://fedorahosted.org/dropwatch/
    >
    > http://prefetch.net/blog/index.php/2011/07/11/using-netstat-and-dropwatch-to-observe-packet-loss-on-linux-servers/

    Hello Eric,

    Okay this is a Fedora-16 VM under KVM with 4 minutes uptime only and dropwatch!

    349 dropped packets in 4 minutes uptime??

    [root@test ~]# uname -r
    3.3.2-6.fc16.x86_64
    [root@test ~]# dropwatch -l kas
    Initalizing kallsyms db
    dropwatch> start
    Enabling monitoring...
    Kernel monitoring activated.
    Issue Ctrl-C to stop monitoring
    1 drops at netlink_unicast+1bc
    3 drops at ip_rcv_finish+f0
    1 drops at __netif_receive_skb+583
    1 drops at ip_rcv+d3
    9 drops at ip_rcv_finish+f0
    9 drops at ip_rcv_finish+f0
    1 drops at __netif_receive_skb+583
    6 drops at ip_rcv_finish+f0
    1 drops at nf_hook_slow+12b
    4 drops at ip_rcv_finish+f0
    1 drops at __netif_receive_skb+583
    4 drops at ip_rcv_finish+f0
    1 drops at nf_hook_slow+12b
    3 drops at ip_rcv_finish+f0
    3 drops at nf_hook_slow+12b
    2 drops at __netif_receive_skb+583
    1 drops at ip6_mc_input+1f6
    7 drops at ip_rcv_finish+f0
    1 drops at ip_rcv_finish+f0
    1 drops at netlink_unicast+1bc
    1 drops at skb_queue_purge+20
    2 drops at __netif_receive_skb+583
    1 drops at ip_rcv_finish+f0
    1 drops at nf_hook_slow+12b
    1 drops at ip_rcv_finish+f0
    1 drops at __netif_receive_skb+583
    19 drops at ip_rcv+d3
    2 drops at ip_rcv_finish+f0
    37 drops at ip_rcv+d3
    2 drops at __netif_receive_skb+583
    43 drops at ip_rcv+d3
    5 drops at ip_rcv_finish+f0
    1 drops at __netif_receive_skb+583
    1 drops at nf_hook_slow+12b
    1 drops at ip6_mc_input+1f6
    7 drops at ip_rcv_finish+f0
    39 drops at ip_rcv+d3
    2 drops at ip6_mc_input+1f6
    1 drops at netlink_unicast+1bc
    1 drops at skb_queue_purge+20
    29 drops at ip_rcv+d3
    7 drops at ip_rcv_finish+f0
    2 drops at __netif_receive_skb+583
    2 drops at ip6_mc_input+1f6
    54 drops at ip_rcv+d3
    3 drops at __netif_receive_skb+583
    2 drops at nf_hook_slow+12b
    3 drops at ip_rcv_finish+f0
    1 drops at ip6_mc_input+1f6
    36 drops at ip_rcv+d3
    6 drops at ip_rcv_finish+f0
    2 drops at __netif_receive_skb+583
    1 drops at nf_hook_slow+12b
    1 drops at icmpv6_rcv+305
    37 drops at ip_rcv+d3
    1 drops at __netif_receive_skb+583
    2 drops at ip_rcv_finish+f0
    4 drops at ip_rcv_finish+f0
    39 drops at ip_rcv+d3
    2 drops at __netif_receive_skb+583
    1 drops at netlink_unicast+1bc
    1 drops at skb_queue_purge+20
    1 drops at nf_hook_slow+12b
    38 drops at ip_rcv+d3
    3 drops at __netif_receive_skb+583
    2 drops at ip6_mc_input+1f6
    1 drops at ip_rcv_finish+f0
    46 drops at ip_rcv+d3
    1 drops at __netif_receive_skb+583
    1 drops at ip_rcv_finish+f0
    ^CGot a stop message
    dropwatch> exit
    Shutting down ...
    [root@test ~]# ifconfig | grep dropped
    RX packets:161562 errors:0 dropped:349 overruns:0 frame:0
    TX packets:2140 errors:0 dropped:0 overruns:0 carrier:0
    RX packets:4 errors:0 dropped:0 overruns:0 frame:0
    TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
    [root@test ~]# uptime
    15:47:00 up 4 min, 3 users, load average: 0.01, 0.04, 0.03
    [root@test ~]# netstat -s
    Ip:
    1553 total packets received
    610 with invalid addresses
    0 forwarded
    0 incoming packets discarded
    345 incoming packets delivered
    478 requests sent out
    71 dropped because of missing route
    Icmp:
    4 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
    echo requests: 2
    echo replies: 2
    4 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
    echo request: 2
    echo replies: 2
    IcmpMsg:
    InType0: 2
    InType8: 2
    OutType0: 2
    OutType8: 2
    Tcp:
    1 active connections openings
    2 passive connection openings
    0 failed connection attempts
    0 connection resets received
    2 connections established
    2353 segments received
    2096 segments send out
    0 segments retransmited
    0 bad segments received.
    0 resets sent
    Udp:
    51 packets received
    0 packets to unknown port received.
    0 packet receive errors
    51 packets sent
    0 receive buffer errors
    0 send buffer errors
    UdpLite:
    TcpExt:
    1 TCP sockets finished time wait in fast timer
    3 delayed acks sent
    2 packets directly queued to recvmsg prequeue.
    2 packets directly received from prequeue
    2009 packets header predicted
    165 acknowledgments not containing data received
    IPReversePathFilter: 82
    IpExt:
    InMcastPkts: 13
    InBcastPkts: 60
    InOctets: 146431
    OutOctets: 63310
    InMcastOctets: 416
    InBcastOctets: 12060

    --
    Chris


    \
     
     \ /
      Last update: 2012-04-26 16:03    [W:0.032 / U:0.808 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site