FreeBSD attempts NAPI...
From: Jeff Garzik <hidden>
Date: 2002-06-16 22:31:06
[snip from release notes]
Selected network drivers now implement a semi-polling mode, which makes systems much more resilient to attacks and overloads. To enable polling, the following options are required in a kernel configuration file:
options DEVICE_POLLING
options HZ=1000 # not compulsory but strongly recommended
The kern.polling.enable sysctl variable will then activate polling mode; with the kern.polling.user_frac sysctl indicating the percentage of CPU time to be reserved for userland. The devices initially supporting polling are dc(4), fxp(4), rl(4), and sis(4). More details can be found in the polling(4) manual page.
[end snip]