On 4/28/07, Quan Sun [off-list ref] wrote:

Hi,
  In these days I met a strange situation, tcp handshake rate is
slow after 2.6.18.8.

  The case is, server accepts connections, and records number of successful
tcp handshakes during last 10 seconds. Client tries to connect to server's
listen port as fast as possible and as many as possible, or in simple words,
client use connect() to flood the server.  In both cases, there are a log of syn
re-send.

  Server's performances varied much, depending on which kernel it was
running. On 2.6.18.8, 10000 successful connections take about 30-40 seconds,
while on 2.6.20 or 2.6.19, it will cost about more than 5 minutes.

Please, look at this by pressing next_in_thread:
http://marc.info/?l=linux-netdev&m=117664202416020&w=2

What are the
#cat /proc/sys/net/ipv4/tcp_mem values for your kernels?

Do you see tcp memory pressure by
#netstat -s ?


Sincerely,
Robert Iakobashvili,
coroberti %x40 gmail %x2e com
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