Re: [PATCH 00/12] x86/crypto: Fix RBP usage in several crypto .S files

[Eric Biggers]

On Thu, Sep 07, 2017 at 11:26:47PM +0200, Ingo Molnar wrote:
> 
> * Eric Biggers <ebiggers3@xxxxxxxxx> wrote:
> 
> > On Thu, Sep 07, 2017 at 09:15:34AM +0200, Ingo Molnar wrote:
> > > 
> > > * Eric Biggers <ebiggers3@xxxxxxxxx> wrote:
> > > 
> > > > Thanks for fixing these!  I don't have time to review these in detail, but I ran
> > > > the crypto self-tests on the affected algorithms, and they all pass.  I also
> > > > benchmarked them before and after; the only noticable performance difference was
> > > > that sha256-avx2 and sha512-avx2 became a few percent slower.  I don't suppose
> > > > there is a way around that?  Otherwise it's probably not a big deal.
> > > 
> > > Which CPU model did you use for the test?
> > > 
> > > Thanks,
> > > 
> > > 	Ingo
> > 
> > This was on Haswell, "Intel(R) Xeon(R) CPU E5-1650 v3 @ 3.50GHz".
> 
> Any chance to test this with the latest microarchitecture - any Skylake derivative 
> Intel CPU you have access to?
> 
> Thanks,
> 
> 	Ingo

Tested with Skylake, "Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz".  The results
were the following which seemed a bit worse than Haswell:

	sha256-avx2 became 3.5% slower
	sha512-avx2 became 7.5% slower

Note: it's tricky to benchmark this, especially with just a few percent
difference, so don't read too much into the exact numbers.

Eric