The primary design goal for NSA HTTP is performance. The architecture
and implementation reflect the effects of an emphasis on efficiency
throughout the entire product development lifecycle. The results
of our emphasis on efficiency are summarized in the following five
performance-enhancing techniques used by NSA HTTP:
Serving content from RAM eliminates
disk latency and I/O bandwidth constraints.
In-kernel implementation decreases transitions between
kernel and user mode.
Tight integration with the TCP protocol stack.
This allows efficient event notification and data transfer. In particular,
a zero-copy send interface reduces data transfer by allowing responses
to be sent directly from the RAM-based cache.
Deferred-interrupt context processing removes the
overhead associated with threads.
Re-use of data structures and other resources
reduces the lengths of critical code paths.
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