Re: [dpdk-dev] [PATCH] app/testpmd: fix IP checksum calculation

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 12/3/2020 1:59 PM, George Prekas wrote:
> Insert a compiler barrier to make sure that the IP checksum calculation
> happens after setting all the fields of the IP header.
> 

Can you please provide the compiler details, and if there is any specific 
instruction on how to reproduce this failure?

> Signed-off-by: George Prekas <prekageo@amazon.com>
> ---
>   app/test-pmd/flowgen.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/app/test-pmd/flowgen.c b/app/test-pmd/flowgen.c
> index acf3e2460..893b4b0b8 100644
> --- a/app/test-pmd/flowgen.c
> +++ b/app/test-pmd/flowgen.c
> @@ -150,6 +150,7 @@ pkt_burst_flow_gen(struct fwd_stream *fs)
>   							   next_flow);
>   		ip_hdr->total_length	= RTE_CPU_TO_BE_16(pkt_size -
>   							   sizeof(*eth_hdr));
> +		rte_compiler_barrier();
>   		ip_hdr->hdr_checksum	= ip_sum((unaligned_uint16_t *)ip_hdr,
>   						 sizeof(*ip_hdr));
>   
>