Bulat Ziganshin wrote:
SM> I think what you're suggesting is that the runtime should detect the SM> amount of physical memory on the system and auto-tune itself to switch SM> to compacting collection when its residency reaches that amount. This SM> is certainly something we could do. Bear in mind that GHC is not SM> necessarily the only process running on the machine, though, and what SM> about running multiple GHCs?
i suggest checking of AVAILABLE physical ram, that is perfectly possible in windows
Ok, fair enough
SM> Also, you can do this by setting your GHC_RTS environment variable. SM> Suppose you have 1G of physical mem. You want GHC to give up when it SM> reaches 1.5G, and you want to switch to compacting collection when the SM> residency reaches 300M. You could do this:
SM> export GHC_RTS='-M1.5G -c20'
SM> because 300M is 20% of 1.5G. Perhaps a better interface would be to SM> allow you to specify exactly the residency at which to switch to compaction.
you mix up two questions:
1) switching from copying to compacting algorithm 2) return memory to OS after GC
No, I was just talking about (1). See my other replies in this thread for comments about (2). Cheers, Simon