Enabling AESNI by default

[Allan Jude]

We've had the AESNI module for quite a few years now, and it has not
caused any problems.

I am wondering if there are any objections to including it in GENERIC,
so that users get the benefit without having to have the "tribal
knowledge" that 'to accelerate kernel crypto (GELI, ZFS, IPSEC, etc),
you need to load aesni.ko'

Userspace crypto that uses openssl or similar libraries is already
taking advantage of these CPU instructions if they are available, by
excluding this feature from GENERIC we are just causing the "out of the
box" experience to by very very slow for crypto.

For example, writing 1MB blocks to a GELI encrypted swap-backed md(4)
device:

with 8 jobs on a 10 core Intel Xeon CPU E5-2630 v4 @ 2.20GHz

fio --filename=/dev/md0.eli --device=1 --name=geli --rw=write --bs=1m
--numjobs=8 --iodepth=16 --end_fsync=1 --ioengine=pvsync
--group_reporting --fallocate=none --runtime=60 --time_based


stock:
write: IOPS=530, BW=530MiB/s (556MB/s) (31.1GiB/60012msec)

with aesni.ko loaded:
write: IOPS=2824, BW=2825MiB/s (2962MB/s) (166GiB/60002msec)


Does anyone have a compelling reason to deny our users the 5x speedup?


-- 
Allan Jude