| Re: [eigen] Status of AVX support |
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On 06.12.2011 14:01, Benoit Jacob wrote:
The difficulty is that taking advantage of AVX without regressing
current performance from SSE will require us to handle *both* 16-byte
and 32-byte packet size and alignment. We will need 16-byte for e.g.
Vector4f, while we will of course want to use 32-byte wherever we can.
I'm afraid, you will lose ABI-compatibility if you use 32-byte alignment
by default. E.g. the size of
struct { char x; Vector4d y; };
will be 48 bytes with 16 byte alignment and 64 bytes with 32 byte alignment.
W.r.t porting to AVX: Be aware that there might be some pitfalls with
AVX-performance:
http://www.agner.org/optimize/blog/read.php?i=142
Christoph
--
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Dipl.-Inf. Christoph Hertzberg
Cartesium 0.051
Universität Bremen
Enrique-Schmidt-Straße 5
28359 Bremen
Tel: (+49) 421-218-64252
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