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

From: Martin Bligh <[email-masked]>
Date: Wed, 29 Nov 2006 15:36:14 -0800

Wenji Wu wrote:
> From: Wenji Wu <[email-masked]>
> 
> 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