On 09/01/2011 04:15 AM, Herbert Xu wrote:
Nikos Mavrogiannopoulos<nmav@xxxxxxxxxx> wrote:
Given my benchmarks have no issues, it is not apparent to me why one
should use AF_ALG instead of cryptodev. I do not know though why AF_ALG
performs so poor. I'd speculate by blaming it on the usage of the socket
API and the number of system calls required.
The target usage of AF_ALG is hardware offload devices that cannot
be directly used in user-space, not software crypto on implementations
such as AESNI/Padlock.
Going through the kernel to use something like AESNI/Padlock or
software crypto is insane.
Given the intended target case, your numbers are pretty much
meaningless as cryptodev's performance can be easily beaten
by a pure user-space implementation.
Actually this is the reason of the ecb(cipher-null) comparison. To
emulate the case of a hardware offload device. I tried to make that
clear in the text, but may not be. If you see AF_ALG performs really bad
on that case. It performs better when a software or a padlock
implementation of AES is involved (which as you say it is a useless
use-case).
Of course, I don't own such an offloading device and cannot test it
directly. If you have different values from a benchmark with an actual
hardware accelerator, I'll be happy to include them.
regards,
Nikos
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