[lwip-users] Can I invoke tcp_tmr() in any rate?

[Chen]

Thanks! Kieran

Any other negative effect besides unnecessarily retramit if tcp_tmr is
invoked at 80ms interval instead of 250ms?


> Date: Tue, 10 Jul 2012 19:39:06
> +0100
> From: Kieran Mansley <address@hidden>
> To: Mailing list for lwIP users <address@hidden>
> Subject: Re: [lwip-users] Could TCP traffic slow down UDP?
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset=us-ascii
>
>
> On 9 Jul 2012, at 19:52, Chen wrote:
>
> > Hi there,
> > 
> > According to lwIP wiki: 
> > 
> > After lwip_init() is called, you must call tcp_tmr() every
> TCP_TMR_INTERVAL milliseconds (default is 250 milliseconds). 
> > 
> > My quesiton: Is there any unpleasant side effect if I call it at a
> rate other than 250ms? Further, how about randomized intervals, say 80ms,
> 83ms, 98ms.... (I tried and haven't notice any yet but would like to hear
> from the gurus to be sure)
> > 
> > I just like to tag this on an existing thread.
>
> Slight variation would be fine.  Calling every 80ms instead of every
> 250 probably isn't as lwIP uses this to control things like TCP
> retransmission.  If it is called too early, it may unnecessarily
> retransmit packets.  But it's easy to convert one to the other: just
> call a function that every third time (roughly 240ms) will call
> tcp_tmr()
>
> Kieran