Garbage collector tuning?

[Jan Wedekind]

Hi,
I wonder whether there is a more performant way to allocate larger memory 
blocks (e.g. 1 MByte). "gc-malloc-pointerless" seems to be much slower 
than "malloc":

                                           user     system      total        
real
    Guile allocate memory              0.003780   0.000020   0.003800 (  
0.003810)
    C allocate memory                  0.000060   0.000000   0.000060 (  
0.000070)

Is there a way to control how often the garbage collector is run?

Thanks
Jan

[1] https://github.com/wedesoft/aiscm/blob/master/bench/bench.scm
[2] https://github.com/wedesoft/aiscm/blob/master/bench/cbench.c