Re: [Qemu-devel] [PATCH RFC 0/7] Translate guest vector operations to host vector operations

[Kirill Batuzov]

On Thu, 16 Oct 2014, Kirill Batuzov wrote:

> > (4) Consider supporting generic vector operations in the TCG?
> 
> I gave it a go and was quite happy with the result. I have implemented the 
> add_i32x4
> opcode which is addition of 128-bit vectors composed of four 32-bit integers
> and used it to translate NEON vadd.i32 to SSE paddd instruction. 

<snip>

> 
> Why I think all this is worth doing:
> 
> (1) Performance. 200% speedup is a lot. My test was specifically crafted and 
> real
>     life applications may not have that much vector operations on average, but
>     there is a specific class of applications where it will matter a lot - 
> media
>     processing applications like ffmpeg.
> 
> (2) Some unification of common operations. Right now every target reimplements
>     common vector operations (like vector add/sub/mul/min/compare etc.). We 
> can
>     do it once in the common TCG code.
> 
> Still there are some cons I mentioned earlier. The need to support a lot of
> opcodes is the most significant in the long run I think. So before I commit my
> time to conversion of more operations I'd like to hear your opinions if this
> approach is acceptable and worth spending efforts.
> 
> Kirill Batuzov (7):
>   tcg: add support for 128bit vector type
>   tcg: store ENV global in TCGContext
>   tcg: add sync_temp opcode
>   tcg: add add_i32x4 opcode
>   target-arm: support access to 128-bit guest registers as globals
>   target-arm: use add_i32x4 opcode to handle vadd.i32 instruction
>   tcg/i386: add support for vector opcodes
> 
>  target-arm/translate.c |   30 ++++++++++-
>  tcg/i386/tcg-target.c  |  103 ++++++++++++++++++++++++++++++++---
>  tcg/i386/tcg-target.h  |   24 ++++++++-
>  tcg/tcg-op.h           |  141 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  tcg/tcg-opc.h          |   13 +++++
>  tcg/tcg.c              |   36 +++++++++++++
>  tcg/tcg.h              |   34 ++++++++++++
>  7 files changed, 371 insertions(+), 10 deletions(-)
> 
> 

Ping? Any more comments?

-- 
Kirill