Re: [Changelog] - Potential performance bottleneck for Linxu TCP

From: Martin Bligh
Date: Wed Nov 29 2006 - 18:36:34 EST


Wenji Wu wrote:
From: Wenji Wu <wenji@xxxxxxxx>

Greetings,

For Linux TCP, when the network applcaiton make system call to move data
from
socket's receive buffer to user space by calling tcp_recvmsg(). The socket
will
be locked. During the period, all the incoming packet for the TCP socket
will go
to the backlog queue without being TCP processed. Since Linux 2.6 can be
inerrupted mid-task, if the network application expires, and moved to the
expired array with the socket locked, all the packets within the backlog
queue
will not be TCP processed till the network applicaton resume its execution.
If
the system is heavily loaded, TCP can easily RTO in the Sender Side.


So how much difference did this patch actually make, and to what
benchmark?

The patch is for Linux kernel 2.6.14 Deskop and Low-latency Desktop

The patch oesn't seem to be attached? Also, would be better to make
it for the latest kernel version (2.6.19) ... 2.6.14 is rather old ;-)

M
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