aes-x86_64 seems slower than the generic implementation
Hi!
When comparing the x86_64 assembly implementation (module aes-x86_64) against the generic AES implementation, I found that the generic implementation was consistenly faster.
Test setup #1:
* cryptsetup 1.6.4
* Linux v3.15-rc1-356-gebfc45e,
https://github.com/Lekensteyn/aur/blob/1d1950/linux-custom/config
* CPU: Intel i5-460M
* Distro: Arch Linux x86_64
Command:
for i in {0..10};do cryptsetup benchmark --cipher aes-xts; done
Test results for n=11, mean (+ standard deviation), enc/dec:
* aes-x86_64: 139.6 (0.68) / 138.5 (0.22)
* aes-generic: 144.8 (0.63) / 144.6 (0.31)
About a month ago, I conducted a similar test on a different machine[1].
* cryptsetup 1.6.4
* QEMU: 1.7.0
* Linux (guest, no modules): v3.14-rc7-59-g08edb33
* Linux (host): v3.14-rc5
* CPU: Intel i7-3770
Test results comparing aes-generic, aes-x86_64 and AESNI (n=3):
generic x86_64 aesni * aes-cbc-128 201/276 200/280 669/2500 * aes-cbc-256 162/205 159/208 492/1835 * aes-xts-256 275/270 272/276 2050/2034
(note, AES-NI performance varies a lot)
Aren't the assembly implementations supposed to be faster?
Kind regards,
Peter