Anatol Belski wrote:
On Fri, January 24, 2014 12:29, Dmitry Stogov wrote:
I would be glad t see any 64-bit performance related improvements.
BTW: the performance degradation is expected. Each pointer is 64-bit
instead of 32-bit => more memory consumption => more CPU cache pressure =>
more CPU cache misses.
On the other hand x86-64 uses more CPU registers, MMX, SSE, passes
arguments in registers, so it's usually faster on small tasks that keep
working set in CPU caches.
Wouldn't then the small parts improve the whole? Fixing the small cases
laying on the surface like implicit 32 vs 64 bit type conversions, better
struct packing and similar measures would already contribute to more
efficient processor and memory usage. That would probably turn many things
even more upside down though:) As yep, potentially 64 bit should be
faster, so it's worth a try to lean PHP towards.
Especially as you welcome it, I would put the topic on my todo after
properly finishing this RFC. Besides potential improvement that's also an
exciting matter.
Much of the 'improved performance' provided by later versions of windows is down to faster processors to hide the extra bloat created. They have adopted having a 32bit version and a 64bit version. Making PHP super efficient on 64bit processors would be useful, but it still misses the point of being able to fall back gracefully to run on 32bit machines? Or is now the time to introduce the same differentiation in all builds of PHP? It is built for the platform?
The main problem here is that changing things to be more 64bit efficient could then make things even worse on 32bit? Yes we need to be modernising, but telling users to 'read the source code' to find out where functions are now returning 64 bit values rather than 32bit ones is not the right approach?
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