Re: [RFC V1 0/7] Introduce AVX512 optimized crypto algorithms

["Dey, Megha" <megha.dey@intel.com>]

Hi Eric,

On 12/21/2020 3:20 PM, Eric Biggers wrote:
> On Fri, Dec 18, 2020 at 01:10:57PM -0800, Megha Dey wrote:
>> Optimize crypto algorithms using VPCLMULQDQ and VAES AVX512 instructions
>> (first implemented on Intel's Icelake client and Xeon CPUs).
>>
>> These algorithms take advantage of the AVX512 registers to keep the CPU
>> busy and increase memory bandwidth utilization. They provide substantial
>> (2-10x) improvements over existing crypto algorithms when update data size
>> is greater than 128 bytes and do not have any significant impact when used
>> on small amounts of data.
>>
>> However, these algorithms may also incur a frequency penalty and cause
>> collateral damage to other workloads running on the same core(co-scheduled
>> threads). These frequency drops are also known as bin drops where 1 bin
>> drop is around 100MHz. With the SpecCPU and ffmpeg benchmark, a 0-1 bin
>> drop(0-100MHz) is observed on Icelake desktop and 0-2 bin drops (0-200Mhz)
>> are observed on the Icelake server.
>>
> Do these new algorithms all pass the self-tests, including the fuzz tests that
> are enabled when CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y?

I had tested these algorithms with CRYPTO_MANAGER_DISABLE_TESTS=n and 
tcrypt, not with
CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y (I wasn't aware this existed, my bad).
I see a couple of errors after enabling it and am working on fixing those.

Megha

>
> - Eric