Vários docs na net descrevem estas opções da seguinte forma:
net.core.netdev_max_backlog :
Maximum number of packets, queued on the INPUT side, when the interface receives packets faster than kernel can process them.
net.ipv4.tcp_max_syn_backlog :
Maximum number of remembered connection requests, which did not yet receive an acknowledgment from connecting client.
Mas não consigo entender totalmente a diferença e a relação entre esses dois valores. net.core.netdev_max_backlog deve ser maior, então net.ipv4.tcp_max_syn_backlog , ou igual ou menor?