2.3.41 - tcp lo interface very slow

[Thorsten Kranzkowski]

On Sun, Jan 30, 2000 at 11:41:31AM +0100, Andi Kleen wrote:
> graham en barnowl.demon.co.uk (Graham Murray) writes:
> > On upgrading from 2.3.40 to 2.3.41, the speed of tcp on the loopback
> > interface has fallen dramatically. I noticed it particularly when
> > connecting to INN on the local system. netstat -to shows a large
> > (approx 45k) Send-Q almost continuously after data transfer has
> > started and data is only transferring at about 2 or Kbytes/sec. 

So I'm not the only one having problems with lo ? :-)
I noticed them because fetchmail was unable to deliver my mail.

I just made a test:
1) booted into 2.3.41pre3
2) netstat -s
3) telnet localhost
   ok, I see the login prompt as expected
4) ^D - abort telnet
5) another telnet localhost
   Trying 127.0.0.1...
   ***but nothing else for at least 5 minutes***
6) ^C - abort
7) 2nd netstat -s 

> The reason is probably the new user context TCP receive code.
> 
> What does netstat -s say after such a session? 

I've attached both netstat outputs of my example.
This is an alpha 'Noname' AXPpci33 ev4 system.

Thorsten

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------------ próxima parte ------------
Ip:
    175 total packets received
    0 forwarded
    0 incoming packets discarded
    166 incoming packets delivered
    175 requests sent out
Icmp:
    9 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 9
    9 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 9
Tcp:
    0 active connections openings
    0 passive connection openings
    0 failed connection attempts
    0 connection resets received
    0 connections established
    0 segments received
    0 segments send out
    0 segments retransmited
    0 bad segments received.
    0 resets sent
Udp:
    157 packets received
    9 packets to unknown port received.
    0 packet receive errors
    166 packets sent
TcpExt:
    TW: 0
    TWRecycled: 0
    TWKilled: 0
    PAWSPassive: 0
    PAWSActive: 0
    PAWSEstab: 0
    DelayedACKs: 0
    DelayedACKLocked: 0
    DelayedACKLost: 0
    ListenOverflows: 0
    ListenDrops: 0
    TCPPrequeued: 0
    TCPDirectCopyFromBacklog: 0
    TCPDirectCopyFromPrequeue: 0
    TCPPrequeueDropped: 0
    TCPHPHits: 0
    TCPHPHitsToUser: 0
------------ próxima parte ------------
Ip:
    253 total packets received
    0 forwarded
    0 incoming packets discarded
    232 incoming packets delivered
    253 requests sent out
Icmp:
    16 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 16
    16 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 16
Tcp:
    2 active connections openings
    0 passive connection openings
    0 failed connection attempts
    0 connection resets received
    0 connections established
    46 segments received
    46 segments send out
    4 segments retransmited
    0 bad segments received.
    5 resets sent
Udp:
    175 packets received
    16 packets to unknown port received.
    0 packet receive errors
    191 packets sent
TcpExt:
    5 resets received for embryonic SYN_RECV sockets
    TW: 0
    TWRecycled: 0
    TWKilled: 1
    PAWSPassive: 0
    PAWSActive: 0
    PAWSEstab: 0
    DelayedACKs: 0
    DelayedACKLocked: 0
    DelayedACKLost: 0
    ListenOverflows: 0
    ListenDrops: 0
    TCPPrequeued: 0
    TCPDirectCopyFromBacklog: 0
    TCPDirectCopyFromPrequeue: 0
    TCPPrequeueDropped: 0
    TCPHPHits: 3
    TCPHPHitsToUser: 0