Re: Re: 64bit and phpng, votes and plans

On 21/05/14 08:41, Arvids Godjuks wrote:

And compare it. Because there is no hard facts about the performance of 64 bit vs 32 bit type usage - just speculation about CPU cache misses and so on. And I learned over the years that people, designing those CPU's, are sneaky and sometimes results defy the logic. And there are hints that actually full 64 bit types may be faster than 32 bit usage for memory optimization.

Having been looking at the hardware side of things again, even older 32bit processors support the MMX/SSX registers and instructions which provide 64bit maths on these processors and the latest AVX extensions already provide 256bit maths on more modern processors since 2011. These registers also provide parallel processing of smaller data sizes being part of the SIMD facility, Compatibility across processors is a problem, but even the higher spec VIA processors support it ... along with support for hardware SHA hashing. If performance is critical, then targeting a specific hardware configuration may help, but there may also be opportunities for selective improvements targeting the available hardware. -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk