Re: [lwip-users] Minimizing TCP send delay with RAW api and multi-threading.

[address@hidden]

Am I assuming correct that you are using the raw api with your own 
threading-mechanisms instead of using the netcon- or socekt API? If so, 
you don't have to wait for your poll callback to be called: you can 
always try to send more data from the sent- or recv- callback. And if 
you need to to do something in an application thread then, use 
tcpip_callback() to get back into tcpip_thread directly - no waiting for 
poll necessary.

Simon


Andrew Foster wrote:
> Kieran,
>
> I apologize, I mixed some verbiage in my description. I'm asking how to
> minimize the delay from application data being ready, to the start of a
> new TCP transmission.
>
> My understanding is that I cannot call a tcp_write from other threads. I
> think that means that I would have to wait until the tcpip_thread polls
> my application to initiate a tcp_write and tcp_output.
>
> Maybe I'm going about this the wrong way. Could I just add a sys_timeout
> to poll my application at a faster rate? This would ensure that the
> tcp_write/output happens in context of the tcpip_thread.
>
> Thanks,
>
> Andrew
>
> -----Original Message-----
> From: Kieran Mansley [mailto:address@hidden
> Sent: Friday, November 12, 2010 04:11
> To: Mailing list for lwIP users
> Subject: Re: [lwip-users] Minimizing TCP send delay with RAW api and
> multi-threading.
>
> On Thu, 2010-11-11 at 15:49 -0500, Andrew Foster wrote:
> > Hello All,
> >
> >
> >
> > Are there any safe tricks to get TCP data sent faster from a non
> > tcpip_thread? Since the RAW api is not safe for concurrent access, it
> > seems the delay will always be a factor of the tcp_tmr intervals
> > (fast&slow). With that in mind, the only way to reduce the delay is to
> > adjust these tmr values to get the TCP_EVENT_POLL to happen more
> > frequently.
> I don't follow how the timer delays will affect the speed of data being
> sent.  The timers are only really involved in this path for
> retransmissions.
>
> Kieran
>
>
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