[fpc-pascal] Heap manager tuning

[denisgolovan]

Hi all

I am trying to debug an issue that seems to be related to FPC heap manager.
Test machine - Linux x64.

It looks like really large memory "overhead" compared to cmem manager.
Test load profile - 50 heavy objects with around 25 large (1Mb - 10Mb) dynamic arrays each.
Those arrays are created in threads.

That allocation takes 10Gb+ under FPC heap manager. Further allocation becomes hardly possible (I have 16Gb on-board).
Meanwhile, cmem allocates around 3Gb. So I can operate >3 times more object set. 

I am pretty sure I don't have any memory leaks (heaptr is enabled all the time).

Any suggestions?
I am willing to sacrifice some allocation performance to decrease total memory consumption if it is necessary. 

-- 
Regards,
Denis Golovan