Re: performance bug of `wc -m` on glibc systems

[Bruno Haible]

With the proposed function-pointer-factory changes, I'm seeing
this speedup on glibc systems:

             num     mbc
  Before    0.056   0.152
  After     0.057   0.089
  -------
  Speedup    1.0     1.7
  factor

Find attached the profiling result.

What you can see:
  - The glibc-compatible rewrite of UTF-8 mbrtowc is about 4.5 times faster
    than the glibc implementation.
  - The glibc wcwidth and the gnulib uc_width are approximately on par,
    regarding speed. uc_width is probably slightly slower, but not
    dramatically.

Bruno

callgrind.out.11605.png
Description: application/kcachegrind