Date: Thu, 6 Dec 2018 16:48:35 -0700 From: John Nielsen <lists@jnielsen.net> To: John Baldwin <jhb@FreeBSD.org> Cc: FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: /dev/crypto not being used in 12-STABLE Message-ID: <E00380E2-581C-4BB6-96B4-DEF3445ED4D4@jnielsen.net> In-Reply-To: <0b3d8b81-4ed2-e900-9f0e-46ac7006a705@FreeBSD.org> References: <A418F9A1-7298-4DA7-A185-BD16941BEC46@jnielsen.net> <CAGMYy3vKez_NR6rtcFDGVsWV=qs%2BiaoAwb-D0ed0zT5og9RbOA@mail.gmail.com> <F67BC606-6210-48DD-B924-FF90C26704A1@jnielsen.net> <0b3d8b81-4ed2-e900-9f0e-46ac7006a705@FreeBSD.org>
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> On Dec 6, 2018, at 4:39 PM, John Baldwin <jhb@FreeBSD.org> wrote: > > On 12/6/18 3:24 PM, John Nielsen wrote: >>> On Dec 6, 2018, at 4:04 PM, Xin LI <delphij@gmail.com> wrote: >>> >>> On Thu, Dec 6, 2018 at 11:37 AM John Nielsen <lists@jnielsen.net> wrote: >>>> >>>> I have upgraded two physical machines from 11-STABLE to 12-STABLE recently (one is 12.0-PRERELEASE r341380 and the other is 12.0-PRERELEASE r341391). I noticed today that neither machine seems to be utilizing /dev/crypto. Typically I see at least ssh/sshd have the device open plus some programs from ports. But 'fuser' doesn't list any processes on either machine: >>>> >>>> # fuser /dev/crypto >>>> /dev/crypto: >>>> >>>> Both machines are running custom kernels that include "device crypto" and "device cryptodev". One of them additionally has "device aesni". >>>> >>>> Is anyone else seeing this? Any idea what would cause it? >>> >>> Your average OpenSSL applications should not use /dev/crypto, if your >>> goal is to utilize AES-NI (which does not require /dev/crypto). On >>> capable systems, AES-NI would be used automatically (and it's faster >>> this way). >> >> Thanks for the response. Is there a way to verify that AES-NI is being used for e.g. ssh? I'm also curious why/when/how the change to not use (or support?) /dev/crypto from base openssl was made. > > I suspect it was something we just didn't test in the flurry of other work > during the OpenSSL upgrade. I did wonder about that. :) > However, it is much faster to use the AES-NI > instructions in userland than to use a system call that copies the data > into a kernel buffer, uses the sames AES-NI instructions, then copies the > data back out again along with the overhead of a pair of user <--> kernel > transitions. If you have an actual crypto offload device (as in a PCI-e > card or something), then you might be interested in /dev/crypto (and we > should fix that eventually), but AES-NI is just faster software crypto and > is best done directly in userland. That makes sense and explains some other comments I was just reading. Is aesni(4) even required if all you want is userland acceleration?
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