On 6/4/24 10:28 AM, Paul Barker wrote: > This patch makes multiple changes that can't be separated: > > 1) Allocate plain RX buffers via a page pool instead of allocating > SKBs, then use build_skb() when a packet is received. > 2) For GbEth IP, reduce the RX buffer size to 2kB. > 3) For GbEth IP, merge packets which span more than one RX descriptor > as SKB fragments instead of copying data. > > Implementing (1) without (2) would require the use of an order-1 page > pool (instead of an order-0 page pool split into page fragments) for > GbEth. > > Implementing (2) without (3) would leave us no space to re-assemble > packets which span more than one RX descriptor. > > Implementing (3) without (1) would not be possible as the network stack > expects to use put_page() or page_pool_put_page() to free SKB fragments > after an SKB is consumed. > > RX checksum offload support is adjusted to handle both linear and > nonlinear (fragmented) packets. > > This patch gives the following improvements during testing with iperf3. > > * RZ/G2L: > * TCP RX: same bandwidth at -43% CPU load (70% -> 40%) > * UDP RX: same bandwidth at -17% CPU load (88% -> 74%) > > * RZ/G2UL: > * TCP RX: +30% bandwidth (726Mbps -> 941Mbps) > * UDP RX: +417% bandwidth (108Mbps -> 558Mbps) > > * RZ/G3S: > * TCP RX: +64% bandwidth (562Mbps -> 920Mbps) > * UDP RX: +420% bandwidth (90Mbps -> 468Mbps) > > * RZ/Five: > * TCP RX: +217% bandwidth (145Mbps -> 459Mbps) > * UDP RX: +470% bandwidth (20Mbps -> 114Mbps) > > There is no significant impact on bandwidth or CPU load in testing on > RZ/G2H or R-Car M3N. > > Signed-off-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx> Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx> [...] MBR, Sergey
