Re: [dpdk-dev] [PATCH] app/testpmd: do not enable Rx offloads by default

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 25 Jan 2018 10:04:11 +0100
Thomas Monjalon <thomas@monjalon.net> wrote:

> 25/01/2018 02:11, Lu, Wenzhuo:
> > > --- a/app/test-pmd/testpmd.c
> > > +++ b/app/test-pmd/testpmd.c
> > > @@ -305,9 +305,7 @@ struct fwd_engine * fwd_engines[] = {
> > >   */
> > >  struct rte_eth_rxmode rx_mode = {
> > >  	.max_rx_pkt_len = ETHER_MAX_LEN, /**< Default maximum frame
> > > length. */
> > > -	.offloads = (DEV_RX_OFFLOAD_VLAN_FILTER |
> > > -		     DEV_RX_OFFLOAD_VLAN_STRIP |
> > > -		     DEV_RX_OFFLOAD_CRC_STRIP),
> > > +	.offloads = 0,  
> > 
> > Change the default behavior may trigger other problems. I think TX offload could be a good reference. Get the capability and check what's supported first, then ignore the not supported functions with printing a warning but not block anything...  
> 
> I agree that we should check the capabilities before requesting an offload.
> But I disagree on another point: we should not enable an offload if the
> user did not request it explicitly. It makes things unclear.
> This is a testing tool, it should be close to the ethdev API behavior.
> 
> Why these offload flags are silently enabled?

Also all virtual devices ignore CRC strip.