Implement optional flag for rotating index

[shayanhabibi]

-d:loonyRotate

This flag indicates that slots are not to be read in sequential order, but rather in a incremental cyclic pattern, stepping over cache lines.

Motivation

Potential reduction in cache coherency overhead from MESI protocol invalidations, false sharing etc

[shayanhabibi]

Is there some benchmark we can challenge this with? There is every potential for this to make almost negligible difference and be a waste of cpu ops on calculating the rotated idx.

[shayanhabibi]

Potentially could also chuck #24 in there to see if combined there is a significant performance benefit.

There is a cost to #24 in that the memory consumption of the Queue increases from 3 pointers (typically 24 bytes) to 3 cachelines (typically 192 bytes). Not a big deal considering the number of instances of the Queue we would actually have.

[disruptek]

Why not export loonyNodeAlignment also? No reason not to merge this.

[disruptek]

Is there some benchmark we can challenge this with? There is every potential for this to make almost negligible difference and be a waste of cpu ops on calculating the rotated idx.

You can benchmark it, after a fashion, against the insideout tests -- rather stressful but probably not utilizing greater than processorCount() cores.

[shayanhabibi]

Rotating flag is now default.

LoonyQueue is now padded to cachelines.

Updated readme.