2022. 4. 13. 오후 4:52에 Igor Russkikh 이(가) 쓴 글:
Hi Igor,
Thank you so much for your review!
>
>
>> v4:
>> - Fix compile warning
>>
>> v3:
>> - Change wrong PPS performance result 40% -> 80% in single
>> core(Intel i3-12100)
>> - Separate aq_nic_map_xdp() from aq_nic_map_skb()
>> - Drop multi buffer packets if single buffer XDP is attached
>> - Disable LRO when single buffer XDP is attached
>> - Use xdp_get_{frame/buff}_len()
>
> Hi Taehee, thanks for taking care of that!
>
> Reviewed-by: Igor Russkikh <irusskikh@xxxxxxxxxxx>
>
> A small notice about the selection of 3K packet size for XDP.
> Its a kind of compromise I think, because with common 1.4K MTU we'll
get wasted
> 2K bytes minimum per packet.
>
> I was thinking it would be possible to reuse the existing page
flipping technique
> together with higher page_order, to keep default 2K fragment size.
> E.g.
> ( 256(xdp_head)+2K(pkt frag) ) x 3 (flips) = ~7K
>
> Meaning we can allocate 8K (page_order=1) pages, and fit three xdp
packets into each, wasting only 1K per three packets.
>
> But its just kind of an idea for future optimization.
>
Yes, I fully agree with your idea.
When I developed an initial version of this patchset, I simply tried
that idea.
I expected to reduce CPU utilization(not for memory optimization), but
there is no difference because page_ref_{inc/dec}() cost is too high.
So, if we tried to switch from MEM_TYPE_PAGE_ORDER0 to
MEM_TYPE_PAGE_SHARED, I think we should use a littie bit different
flipping strategy like ixgbe.
If so, we would achieve memory optimization and CPU optimization.
Thanks a lot,
Taehee Yoo
> Regards,
> Igor
