[PATCH v1 3/6] x86: Remove mem{move|cpy}-ssse3

[Mayshao-oc]

On Tue, Mar 29, 2022 at 10:57 AM Noah Goldstein<goldstein.w.n@gmail.com> wrote:


>On Mon, Mar 28, 2022 at 9:51 PM Mayshao-oc <Mayshao-oc@zhaoxin.com> wrote:
> >
> > On Mon, Mar 28, 2022 at  9:07 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> >
> > > On Mon, Mar 28, 2022 at 1:10 AM Mayshao-oc <Mayshao-oc@zhaoxin.com> wrote:
> > > >
> > > > On Fri, Mar 25, 2022 at 6:36 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > > >
> > > > > With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
> > > > > SSSE3. As a result its no longer with the code size cost.
> > > > > ---
> > > > > sysdeps/x86_64/multiarch/Makefile          |    2 -
> > > > > sysdeps/x86_64/multiarch/ifunc-impl-list.c |   15 -
> > > > > sysdeps/x86_64/multiarch/ifunc-memmove.h   |   18 +-
> > > > > sysdeps/x86_64/multiarch/memcpy-ssse3.S    | 3151 --------------------
> > > > > sysdeps/x86_64/multiarch/memmove-ssse3.S   |    4 -
> > > > > 5 files changed, 7 insertions(+), 3183 deletions(-)
> > > > > delete mode 100644 sysdeps/x86_64/multiarch/memcpy-ssse3.S
> > > > > delete mode 100644 sysdeps/x86_64/multiarch/memmove-ssse3.S
> > > >
> > > > On some platforms, such as Zhaoxin, the memcpy performance of SSSE3
> > > > is better than that of AVX2, and the current computer system has sufficient
> > > > disk capacity and memory capacity.
> > >
> > > How does the SSSE3 version compare against the SSE2 version?
> >
> > On some Zhaoxin processors, the overall performance of SSSE3 is about
> > 10% higher than that of SSE2.
> >
> >
> > Best Regards,
> > May Shao
>
> Any chance you can post the result from running `bench-memset` or some
> equivalent benchmark? Curious where the regressions are. Ideally we would
> fix the SSE2 version so its optimal.

Bench-memcpy on Zhaoxin KX-6000 processor shows that, when length <=4 or
length >= 128, memcpy SSSE3 can achieve an average performance improvement
of 25% compared to SSSE2.

I have attached the test results, hope this is what you want to see.

> > > > It is strongly recommended to keep the SSSE3 version.
> > > >
> > >
> > >
> > > --
> > > H.J.
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