Re: [dpdk-dev] dpdk-2.0.0: crash in ixgbe_recv_scattered_pkts_vec->_recv_raw_pkts_vec->desc_to_olflags_v

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2015-06-30 08:49, Gopakumar Choorakkot Edakkunni:
> I am starting to tryout dpdk-2.0.0 with a simple Rx routine very
> similar to the l2fwd example - I am running this on a c3.8xlarge aws
> sr-iov enabled vpc instance (inside the vm it uses ixgbevf driver).

You mean you are using SR-IOV from Amazon, right?
Do you have more hardware details?

> Once in every 10 minutes my application crashes in the recieve path.
> And whenever I check the crash reason its because it always has three
> packets in the burst array (I have provided array size of 32) instead
> of the four that it tries to collect in one bunch. And inside
> desc_to_olflags_v(), theres the assumption that there are four
> packets, and obviously it crashes trying to access the fourth buffer.

Did you try to disable CONFIG_RTE_IXGBE_INC_VECTOR?

> With a brief look at the code, I really cant make out how its
> guaranteed that we will always have four descriptors fully populated ?
> After the first iteration, the loop does break out if (likely(var !=
> RTE_IXGBE_DESCS_PER_LOOP)), but how about the very first iteration
> where we might not have four ?
> 
> Any thoughts will be helpful here, trying to get my app working for
> more than 10 minutes :)

Not needed. A DPDK application is fast enough to do the job in 10 minutes ;)