[minipci1321]

Not speaking specifically of the OP case, but CPU gets less and less involved in the datapath starting from a certain requirement of the max throughput. Insisting on it's going through the CPU still would raise the bar on the CPU (as a consequence, more fast RAM and increased overall power consumption, shorter battery life).

> with a firmware I can't audit.

In modern fast datapaths, there is a good deal of hardware acceleration involved, the firmware code would probably be incomprehensible without intimately knowing these.

[devereaux]

Yes, there would be a IO load.

Tradeoffs, as always.

For some applications, I want low latency and high throughput. For others, I want security.