netdev - Slow tcp handshakes rate of 2.6.20 and 2.6.19

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <e810d8480704271935l3a597d89g260bcb185c457937@mail.gmail.com>
Date:	Sat, 28 Apr 2007 10:35:03 +0800
From:	"Quan Sun" <cfk.quan@...il.com>
To:	netdev@...r.kernel.org
Subject: Slow tcp handshakes rate of 2.6.20 and 2.6.19

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.

   It seems there is some a mechanism which prevents connect() flood.
My problem is, is the mechanism exist, or there is some other reason(s)
for why 2.6.18 varies from 2.6.19/2.6.20?

   All these config files are all the same, tcp related options are,
CONFIG_INET_TCP_DIAG=m
CONFIG_TCP_CONG_ADVANCED=y
CONFIG_TCP_CONG_BIC=y
CONFIG_TCP_CONG_CUBIC=m
CONFIG_TCP_CONG_WESTWOOD=m
CONFIG_TCP_CONG_HTCP=m
CONFIG_TCP_CONG_HSTCP=m
CONFIG_TCP_CONG_HYBLA=m
CONFIG_TCP_CONG_VEGAS=m
CONFIG_TCP_CONG_SCALABLE=m
CONFIG_TCP_CONG_LP=m
CONFIG_TCP_CONG_VENO=m
CONFIG_IP_VS_PROTO_TCP=y
CONFIG_NETFILTER_XT_MATCH_TCPMSS=m
CONFIG_IP_NF_TARGET_TCPMSS=m

-- 
Quan Sun
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html