Re: OGR-NG on Xeon Phi?

Roman Trunov <[email protected]> Thu, 13 Dec 2012 16:17:27 +0400
Newsgroups gmane.comp.distributed-net.rc5
Organization Proxyma Communications
Message-ID <[email protected]>
[email protected] wrote:

> Additional, the Phi-Cores are equipped with 512Bit SIMD-Units.  I dont know any detail of their architecture or commandset, but maybe 
this could be a great benefit for OGR?

The answer really depends on architecture and command set of these 
units, and latencies of operations.

OGR-NG operates on bitmaps of 256 bits long, 512 bits units looks 
excessive. More important is which kinds of rotations are supported. 
High-bitness SIMD architectures usually cannot rotate a register by 
arbitrary number of bits, which is required for OGR. Instead, you have 
to use two operations - rotate by a whole number of bytes first, then by 
remaining 0-7 bits. If new command set could overcome this limitation, 
it could give us some gain. Otherwise, it's quite useless.

Roman
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