[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lwip-users] tcp_tmr - TCP_TMR_INTERVAL

From: Timmy Brolin
Subject: Re: [lwip-users] tcp_tmr - TCP_TMR_INTERVAL
Date: Fri, 01 Sep 2006 19:18:45 +0200
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax)

You are right.

I'am actually a bit surprised that the timer is running at only 250ms intervals.. Could this be a performance bottleneck? Are retransmissions not handled by the timers? That's a minimum 250ms penalty for every retransmission...

Timmy Brolin

Kieran Mansley wrote:

On Thu, 2006-08-31 at 23:29 +0200, Timmy Brolin wrote:
As long as TCP_TMR_INTERVAL is #defined to the interval by which you actually call the timer function, any value should be fine. Anything below 250 or so should be fine.

That may be what was intended with those defines, but the code doesn't
use them that way (in 1.1.0 at least - I don't have 1.1.1 to hand to
check that).  The tcp_fast_tmr() function is called every time tcp_tmr()
is called, and the tcp_slow_tmr() function is called every other time.
There is no check there to divide the required time by TCP_TMR_INTERVAL
before deciding whether to invoke either the fast or slow timer
functions.  This would be good idea though if people need the
flexibility of calling tcp_tmr() more frequently.


lwip-users mailing list

reply via email to

[Prev in Thread] Current Thread [Next in Thread]