Marvell EBU 32-bit performance benchmarks (VFPv3-D16 vs NEON builds, Turris Omnia).
rosenp at gmail.com
Thu Oct 21 13:31:00 PDT 2021
On Thu, Oct 21, 2021 at 12:19 PM Kabuli Chana <anome at shaw.ca> wrote:
> For me the argument was not about whether there should 2, but whether
> the change to vfpv3-d16 was the right choice as the 1. openssl is of
> course preordained to run NEON SIMD code so no change would be expected,
> but a benefit is seen on WG. I would suggest that is the result of 16
> vs. 32 FP registers being available, and nothing to do with NEON; i.e.
> vfpv3-d16 vs. vfpv3. The result being smaller and faster due to more
> concise FP code generation due to less FP register rejigging.
I call BS.
WireGuard does not use floating point.Just fixed point arithmetic,
like most crypto. WireGuard being faster probably has to do with its
usage of NEON assembly.
> On 2021-10-21 09:38, Rui Salvaterra wrote:
> > Hi, guys,
> > So, last meeting I proposed splitting the 32-bit mvebu target in
> > vfpv3-d16 and neon subtargets. It seems this subject comes up every
> > couple of years, or so. This time I hope to show solid evidence on why
> > it would be an exercise in futility, closing the matter once and for
> > all. In order to do so, I tested the performance of openssl speed (10
> > seconds time limit), cryptsetup benchmark and iperf3 over WireGuard.
> > Here are the results for each build:
> > VFPv3-D16:
> > https://paste.debian.net/1216262/
> > NEON:
> > https://paste.debian.net/1216261/
> > These are master builds from my stmvebu branch, running Linux 5.10.75.
> > The configuration is custom, but each build differs only in the
> > CPU_SUBTYPE (vfpv3-d16 vs neon).
> > Cheers,
> > Rui
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