[fpc-pascal] Heavy heap fragmentation issue

[Ryan Joseph]

> On Jun 2, 2019, at 12:49 PM, Martok <listbox at martoks-place.de> wrote:
> 
> Hi all,
> 
> I'm having a problem here in a sequential image processing application that
> seems to test a particularly bad operation mode for the RTL heap manager (on
> Windows, but I don't think this matters here).
> The work load looks like this: load "normal sized" image, do some processing,
> calculate a few values, create thumbnail in memory, next. By "normal sized" I
> mean something like 35MB uncompressed (regular DSLR resolution) and smaller.
> It's threaded code, but I'm describing the single worker operation here.
> 
> This appears to trigger insane memory fragmentation: after execution on 40 test
> files, I'm left with 250MB working set, while GetHeapStatus only reports 600k
> used (which seems correct, my data structures add up to 500k). This is never
> released to the OS. In fact, I've had to set the LAA flag just so that the
> program can work on the real data at all, with some 2.6GB working set for 1.07MB
> of used memory.
> 
> Is there any tuning option that could use maybe fix that? Some growing or
> reallocating flag or something?
> 
> 
> As a quick test, I've tried my partial port of FastMM4 which works just fine, no
> fragmentation and peaks at 40MB used memory, which fits with the largest image.
> 
> But this is such a reproducible test case, maybe there is something that can be
> done to improve the RTL MM?
> 
> -- 
> Regards,
> Martok

can you break it down into a test program and post?

Regards,
	Ryan Joseph