Re: [Qemu-arm] [Qemu-devel] [PATCH 0/7] Improve buffer_is_zero

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

cc'ing in Liang Li who did the original avx2 code.

Dave


* Richard Henderson (rth@twiddle.net) wrote:
> Patches 1-3 remove the use of ifunc from the implementation.
> 
> Patch 5 adjusts the x86 implementation a bit more to take
> advantage of ptest (in sse4.1) and unaligned accesses (in avx1).
> 
> Patches 2 and 6 are the result of my conversation with Vijaya
> Kumar with respect to ThunderX.
> 
> Patch 7 is the result of seeing some really really horrible code
> produced for ppc64le (gcc 4.9 and mainline).
> 
> This has had limited testing.  What I don't know is the best way
> to benchmark this -- the only way I know to trigger this is via
> the console, by hand, which doesn't make for reasonable timing.
> 
> 
> r~
> 
> 
> Richard Henderson (7):
>   cutils: Remove SPLAT macro
>   cutils: Export only buffer_is_zero
>   cutils: Rearrange buffer_is_zero acceleration
>   cutils: Add generic prefetch
>   cutils: Rewrite x86 buffer zero checking
>   cutils: Rewrite aarch64 buffer zero checking
>   cutils: Rewrite ppc buffer zero checking
> 
>  configure             |  21 +-
>  include/qemu/cutils.h |   2 -
>  migration/ram.c       |   2 +-
>  migration/rdma.c      |   5 +-
>  util/cutils.c         | 526 +++++++++++++++++++++++++++++++++-----------------
>  5 files changed, 352 insertions(+), 204 deletions(-)
> 
> -- 
> 2.7.4
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK