[ofa-general] IPoIB post_send failed

[Pradeep Satyanarayana]

Hal Rosenstock wrote:
> Hi,
>  
> I'm seeing the following messages from IPoIB:
> ib0: post_send failed
> ib0: post_send failed
> ib0: post_send failed
> ib0: post_send failed
> ib0: post_send failed
> ib0: post_send failed
> NETDEV WATCHDOG: ib0: transmit timed out
> ib0: transmit timeout: latency 1374 msecs
> ib0: queue stopped 1, tx_head 140245691, tx_tail 140245565
>  
> What are the possible (and most likely) causes of post_send failures ? I
> went through the code for all the errors (some at the driver level) but
> none popped out at me.
>  

Is it possible that the receiver is overwhelmed and hence the tx_ring is full?
Is this a UDP application?

> Once the transmit queue is stopped, does the interface need to be taken
> down and then back up to restart this ?

One does not need to take down the interface. It should be able to recover on it's
own. There is a timer that kicks in and checks if the tx_ring is still full or not-
the transmits should start again. Thanks!

Pradeep