This change was also posted in patch #10160 with the following info in the original submission:


I have made a patch that adds an object pool for octave_base_scalar and
its derived classes, to decrease malloc and free usage.

Code like:

    function i = foo ()
            tic;
            for i = 1:100000
                    i = 1+2+3+4+5+6+7;
            end
            toc;
    end

has a speed increase of about 13% on my machine and the amount of mallocs
decreases from 1,1 million to 440 000.

The patch works fine on my x64 Debian machine, but should probably be tested
on a Windows build, because C++ thread_local support is kinda quirky.

The object pool size is set to 8, but could probably be tuned somewhat.

From Petter Tomner <petter>, extracted from the zip file attached to the following comment in the discourse thread "WIP stack VM f\
or Octave": https://octave.discourse.group/t/wip-stack-vm-for-octave/2884/10

Make octave_scalar_base an its descendents use an object pool to
decrease malloc and free usage. Same for some stack frames.