Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] crypto: x86/aesni - implement accelerated CBCMAC, CMAC
 and XCBC shashes
From:   Ben Greear <greearb@candelatech.com>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Eric Biggers <ebiggers@kernel.org>
References: <20200802090616.1328-1-ardb@kernel.org>
 <25776a56-4c6a-3976-f4bc-fa53ba4a1550@candelatech.com>
 <CAMj1kXFAbip567hFaFtoqdevrSEpqFOGQ1+ejL98XrDOaTeggA@mail.gmail.com>
 <9c137bbf-2892-df7a-e6fa-8cce417ecd45@candelatech.com>
 <CAMj1kXFnfYKj1JE4NLsxXtaeKuAOKyBYDbayLr-mHDUYqnV1bA@mail.gmail.com>
 <d7f44f7a-d00e-cef4-5c91-86119e240038@candelatech.com>
Organization: Candela Technologies
Message-ID: <391c30de-4746-940c-6585-d69c27f2f4cb@candelatech.com>
Date:   Wed, 23 Sep 2020 04:03:31 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.11.0
MIME-Version: 1.0
In-Reply-To: <d7f44f7a-d00e-cef4-5c91-86119e240038@candelatech.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-MW
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 8/4/20 12:45 PM, Ben Greear wrote:
> On 8/4/20 6:08 AM, Ard Biesheuvel wrote:
>> On Tue, 4 Aug 2020 at 15:01, Ben Greear <greearb@candelatech.com> wrote:
>>>
>>> On 8/4/20 5:55 AM, Ard Biesheuvel wrote:
>>>> On Mon, 3 Aug 2020 at 21:11, Ben Greear <greearb@candelatech.com> wrote:
>>>>>
>>>>> Hello,
>>>>>
>>>>> This helps a bit...now download sw-crypt performance is about 150Mbps,
>>>>> but still not as good as with my patch on 5.4 kernel, and fpu is still
>>>>> high in perf top:
>>>>>
>>>>>       13.89%  libc-2.29.so   [.] __memset_sse2_unaligned_erms
>>>>>         6.62%  [kernel]       [k] kernel_fpu_begin
>>>>>         4.14%  [kernel]       [k] _aesni_enc1
>>>>>         2.06%  [kernel]       [k] __crypto_xor
>>>>>         1.95%  [kernel]       [k] copy_user_generic_string
>>>>>         1.93%  libjvm.so      [.] SpinPause
>>>>>         1.01%  [kernel]       [k] aesni_encrypt
>>>>>         0.98%  [kernel]       [k] crypto_ctr_crypt
>>>>>         0.93%  [kernel]       [k] udp_sendmsg
>>>>>         0.78%  [kernel]       [k] crypto_inc
>>>>>         0.74%  [kernel]       [k] __ip_append_data.isra.53
>>>>>         0.65%  [kernel]       [k] aesni_cbc_enc
>>>>>         0.64%  [kernel]       [k] __dev_queue_xmit
>>>>>         0.62%  [kernel]       [k] ipt_do_table
>>>>>         0.62%  [kernel]       [k] igb_xmit_frame_ring
>>>>>         0.59%  [kernel]       [k] ip_route_output_key_hash_rcu
>>>>>         0.57%  [kernel]       [k] memcpy
>>>>>         0.57%  libjvm.so      [.] InstanceKlass::oop_follow_contents
>>>>>         0.56%  [kernel]       [k] irq_fpu_usable
>>>>>         0.56%  [kernel]       [k] mac_do_update
>>>>>
>>>>> If you'd like help setting up a test rig and have an ath10k pcie NIC or ath9k pcie NIC,
>>>>> then I can help.  Possibly hwsim would also be a good test case, but I have not tried
>>>>> that.
>>>>>
>>>>
>>>> I don't think this is likely to be reproducible on other
>>>> micro-architectures, so setting up a test rig is unlikely to help.
>>>>
>>>> I'll send out a v2 which implements a ahash instead of a shash (and
>>>> implements some other tweaks) so that kernel_fpu_begin() is only
>>>> called twice for each packet on the cbcmac path.
>>>>
>>>> Do you have any numbers for the old kernel without your patch? This
>>>> pathological FPU preserve/restore behavior could be caused be the
>>>> optimizations, or by other changes that landed in the meantime, so I
>>>> would like to know if kernel_fpu_begin() is as prominent in those
>>>> traces as well.
>>>>
>>>
>>> This same patch makes i7 mobile processors able to handle 1Gbps+ software
>>> decrypt rates, where without the patch, the rate was badly constrained and CPU
>>> load was much higher, so it is definitely noticeable on other processors too.
>>
>> OK
>>
>>> The weak processor on the current test rig is convenient because the problem
>>> is so noticeable even at slower wifi speeds.
>>>
>>> We can do some tests on 5.4 with our patch reverted.
>>>
>>
>> The issue with your CCM patch is that it keeps the FPU enabled for the
>> entire input, which also means that preemption is disabled, which
>> makes the -rt people grumpy. (Of course, it also uses APIs that no
>> longer exists, but that should be easy to fix)
>>
>> Do you happen to have any ballpark figures for the packet sizes and
>> the time spent doing encryption?
>>
> 
> My tester reports this last patch appears to break wpa-2 entirely, so we
> cannot test it as is.

Hello,

I'm still hoping that I can find some one to help enable this feature again
on 5.9-ish kernels.

I don't care about preemption being disabled for long-ish times, that is no worse than what I had
before, so even if an official in-kernel patch is not possible, I can carry an
out-of-tree patch.

Thanks,
Ben