On 6/14/19 4:53 PM, Jason Baron wrote:
>
>
> On 6/13/19 5:20 PM, Willem de Bruijn wrote:
>>>>> @@ -237,6 +237,7 @@ static inline int find_next_netdev_feature(u64
>>>>> feature, unsigned long start)
>>>>> NETIF_F_GSO_GRE_CSUM | \
>>>>> NETIF_F_GSO_IPXIP4 | \
>>>>> NETIF_F_GSO_IPXIP6 | \
>>>>> + NETIF_F_GSO_UDP_L4 | \
>>>>> NETIF_F_GSO_UDP_TUNNEL | \
>>>>> NETIF_F_GSO_UDP_TUNNEL_CSUM)
>>>>
>>>> Are you adding this to NETIF_F_GSO_ENCAP_ALL? Wouldn't it make more
>>>> sense to add it to NETIF_F_GSO_SOFTWARE?
>>>>
>>>
>>> Yes, I'm adding to NETIF_F_GSO_ENCAP_ALL (not very clear from the
>>> context). I will fix the commit log.
>>>
>>> In: 83aa025 udp: add gso support to virtual devices, the support was
>>> also added to NETIF_F_GSO_ENCAP_ALL (although subsequently reverted due
>>> to UDP GRO not being in place), so I wonder what the reason was for that?
>>
>> That was probably just a bad choice on my part.
>>
>> It worked in practice, but if NETIF_F_GSO_SOFTWARE works the same
>> without unexpected side effects, then I agree that it is the better choice.
>>
>> That choice does appear to change behavior when sending over tunnel
>> devices. Might it send tunneled GSO packets over loopback?
>>
>>
>
> I set up a test case using fou tunneling through a bridge device using
> the udpgso_bench_tx test where packets are not received correctly if
> NETIF_F_GSO_UDP_L4 is added to NETIF_F_GSO_SOFTWARE. If I have it added
> to NETIF_F_GSO_ENCAP_ALL, it does work correctly. So there are more
> fixes required to include it in NETIF_F_GSO_SOFTWARE.
>
> The use-case I have only requires it to be in NETIF_F_GSO_ENCAP_ALL, but
> if it needs to go in NETIF_F_GSO_SOFTWARE, I can look at what's required
> more next week.
>
Hi,
I haven't had a chance to investigate what goes wrong with including
NETIF_F_GSO_UDP_L4 in NETIF_F_GSO_SOFTWARE - but I was just wondering if
people are ok with NETIF_F_GSO_UDP_L4 being added to
NETIF_F_GSO_ENCAP_ALL and not NETIF_F_GSO_SOFTWARE (ie the original
patch as posted)?
As I mentioned that is sufficient for my use-case, and its how Willem
originally proposed this.
Thanks,
-Jason
> Thanks,
>
> -Jason
>
>>
>>> I agree that NETIF_F_GSO_SOFTWARE seems conceptually more logical and
>>> further I think it adds support for more 'virtual' devices. For example,
>>> I tested loopback with NETIF_F_GSO_UDP_L4 being added to
>>> NETIF_F_GSO_SOFTWARE and it shows a nice performance gain, whereas
>>> NETIF_F_GSO_ENCAP_ALL isn't included for loopback.
>>>
>>> Thanks,
>>>
>>> -Jason
