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

[Dey, Megha]

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