Irrelevant. Would you recommend to eliminate SSE1-4 since the difference is only a billionth of a second between a x87 and SSE* operation?

That is a complete red herring.

The point is that if paying the cost of 5 nanoseconds in one place enables the saving of 50 or 500 nanoseconds somewhere else, the trade off is eminently worth while.

I'm always in favour of optimising code that gets reused by many projects with as many different performance criteria as the Perl runtime; but you have to target your optimisations. And obsessing about 5 nanoseconds in one place without considering the wider implications -- the greater net gain optimisation possibilities that will be disabled -- by opting for a given micro-optimisation, is naive and shortsighted.

Win32 Perl's architecture emulates various parts of POSIX in win32.c or in MS's CRT, this layer is less than ideally designed, its actually crap IMO.

Ah! Something we can agree on. :)

As for the perl development archeology; it is of little interest. We are where we are now. How we got here doesn't matter.

The only interesting questions are:

1. Going forward, is there anyway to improve what we have now?

   I've expounded at length that I believe that there are ways to improve the current status quo.

   But, I feel that to do so would require considerably more radical changes than are currently ever considered viable.

   The problem -- of perl's lack-lustre performance -- needs to first be tackled top down, root and branch, looking at what Perl expends most of its cycles doing; and how that might be improved.

   Only once the top-down flow of code has been improved would it be worth doing bottom up micro-optimisations.

2. Is there the collective will to tackle the task?

   I think recent related discussion here answer that question.

I fail to see any relevance -- to anything -- in all your discussion of long dead versions of windows.

As I said above, in the wider scheme of things, the 5 nanoseconds we are discussing here are irrelevant.