Re: [lwip-users] tcp_enqueue: too long queue

[Kieran Mansley]

On Thu, 2010-09-02 at 12:44 +0200, gregoryhouse wrote:
> Hi,
> 
> What would cause the following warnings:
> 
> tcp_enqueue: too long queue 16 (max 16)
> tcp_enqueue: too long queue 16 (max 16)
> tcp_enqueue: queue too long 17 (16)
> tcp_enqueue: queue too long 17 (16)
> tcp_enqueue: too long queue 16 (max 16)
> 
> I have a lwIP with FreeRTOS. The application works OK, but when I want
> to refresh the www site (httpd_raw server), I see on console those
> warnings.

It means that your application is sending things faster than the network
can take them, and that the TCP send queue has reached its
(configurable) limit.  This limit is there and normally set quite small
in lwIP to prevent it using a lot of memory.  If the limit is reached
tcp_write() will return an error and the application or higher-level API
will have to try and send again later

Kieran