Re: [PATCH v2] aarch64: thunderx2 memmove performance improvements

[Anton Youdkevitch <anton dot youdkevitch at bell-sw dot com>]

On 5/1/2019 14:34, Szabolcs Nagy wrote:
> On 30/04/2019 13:40, Anton Youdkevitch wrote:
> > Now with the patch
> >
> > On Tue, Apr 30, 2019 at 03:37:32PM +0300, Anton Youdkevitch wrote:
> > > Here is the patch to make memove use thunderx2
> > > capabilities more efficient.
> > >
> > > The performance improvement is about 20%-30% for
> > > larger cases and about 1%-5% for smaller cases.
>
> this or similar statement about the performance
> improvement on thunderx2 should be added to the
> commit message.
Will do.

> > > Used SIMD load/store instead of GPR for overlapping
> > > forward move.
> > >
> > > Reused existing memcpy implementation for small or
> > > overlapping backward move.
> > >
> > > Fixed the existing memcpy implementation to allow it
> > > to deal with the overlapping case.
> > >
> > > Simplified loop tails in the memcpy implementation -
> > > use branchless overlapping sequence of fixed length
> > > load/stores instead of branching depending on the
> > > size.
> > >
> > > Fixed some missing optimization mainly wrt ldr/str
> > > to ldp/stp conversion.
> > >
> > > Added __memmove_thunderx2 to the list of the
> > > available implementations.
> > >
> > >
> > > make check on linux/aarch64 - no regressions
> > > make bench on thunderx2     - improvements
> > >
> > > Looks OK?
> > >
> > > * sysdeps/aarch64/multiarch/ifunc-impl-list.c: Added
> > >    __memmove_thunderx2 to the list of implementations
> > > * sysdeps/aarch64/multiarch/memmove.c: Likewise
> > > * sysdeps/aarch64/multiarch/memcpy_thunderx2.S:
> > >    (__memmove_thunderx2): rewritten using SIMD ld/st
> > >    (__memcpy_thunderx2): fixed to handle overlapping cases
>
> This is ok to commit with the commit message fixed.
OK, thanks!