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Re: warning: eth_recv out of MBUFs


On Fri, Jun 27, 2003 at 02:43:06PM +0200, Adolfo Lucha wrote:
> Hello,
> 

> I faced a behaviour which i do not understand. When I ping with
> 65000 bytes (high packets traffic) to my target it is printing
> *warning: eth_recv out of MBUFs*. 

This means its run out of buffers to receive packets into. This is a
normal condition when your CPU cannot keep up with the network
traffic. You can disable this message. Modify your configuration so
that CYGPKG_IO_ETH_DRIVERS_WARN_NO_MBUFS is disables. Disabling this
will also help it cope with the overload since if its not wasting time
printing a warning it can spend more time actually processing packets.

> Afterwards some interfaces are not working in the input direction
> but they are working in the output direction. 

OK. The fact you can send means that running out of MBUFs is not the
root problem. The same pool of MBUFS is used for sending and
receiving. So it most of recovered from the overload and returned some
MBUFs to the pool.

> For example the thread
> which call read (non blocking mode) will returns ever without data,
> even there are input interrupts.
> 
> Some times the IP SNMP packets does not reaches my SNMP-Agent
> thread. The stack means no thread were waiting for that data. The
> thread is able to send SNMP packets (traps) but not to receive
> set/get SNMP packets.

This all suggests the receive engine of the ethernet device you are
using has locked up or something has gone wrong with the receive
buffers. Check that after this overload condition has occurred to see
if the hardware is generating any interrupts for received
packets. Also make sure the hardware does actually have some buffers
in its receive ring/list to put received packets into.

   Andrew

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