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Release memory after a function is completed

crizos

Hi all,

Assume that we have a dummy test function which its definition is:

procedure( test() let( (x) x = list( 2 3 ) ) )


If I run the profiler for this procedure I see that the total memory that have been allocated for this function is 96 bytes, while list command needs 48 bytes. Let's say that we need this function to be used 10000 consecutive times for a reason. Profiler reports that the allocated memory for this operation raises up to 468 KByte because of list command which need this much amount of bytes (I guess the numbers may differ in different machines).

Is it possible to reduce the memory that is captured for this operation in any way? Or make that memory available again after the operation is finished? memoryAllocated() function indicates that once my processes are over, the memory remains captive.

Also, I tried to force-use the gc() function but with no results, while operated time was increased.

 

Chris

  • Hi Chris,

    You generally do not need to worry about this, as the system will garbage collect automatically as it needs to. Essentially it keeps a pool of each kind of object (list cells in this case) and when it has run out, it triggers a garbage collection before allocating more. Calling gc() explicitly is something that should only rarely be done in some high memory applications if you really need to control precisely when garbage collection occurs, but in general I wouldn't advise calling it in a program.

    Note that the memory won't be returned to the OS - so you wouldn't expect memoryAllocated() to reduce. Any unreferenced list cells are available to be garbage collected and re-used in subsequent operations. Many applications in Linux and other UNIX systems are similar - freeing memory doesn't necessarily return it to the OS.

    Trying to optimise memory in such a simple situation is unlikely to be worth the effort, similar to it being pointless doing performance optimisation at too low a level (or too soon). There are of course efficient ways of processing large amounts of data which can minimise potential garbage, but that's not something you can really extrapolate from such a trivial example as this.

    Kind Regards,

    Andrew.

  • in reply to Andrew Beckett

    Hi Andrew,

    In a way, this example is not so far from the reality, but thank you for the answer.

    Sincerely,

    Chris

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