Profiling the memory in D
schveiguy at gmail.com
Wed Dec 4 15:38:36 UTC 2019
On 12/4/19 3:10 AM, Erdem wrote:
> I am used to have cool tools like valgrid massif to visualize the memory
> usage from C++ but in D it seems I am blind folded looking for the problem.
> Until now I tried:
> --vgc option which show million things which makes it not useful
> which seems to slow down my program like *200 times and I have some
> operation depending on time which makes creating the real case of the
> application impossible. The observation itself effect the experiment
> very badly.
> Since this options are not useful for me, I tried to put debug logs in
> critical places to estimate where I am losing memory. I couldn't find a
> D native call to get the memory usage of the program. I had to call a
> shell command which also slows down the app. This slow down causes me to
> not be able to put this debug log too many places or in critical loops.
> I manage to narrow it down a bit. Than I wanted to check the object
> instances to find out which objects are getting bigger. I tried
> GC.sizeOf(&object) which always prints 0. GC.sizeOf also does not works
> with associative arrays , I don't see any usefull case than
> That is the background of my questions and my questions are:
> Is there a better way to visualize the memory in D something like
> valgrid massif?
> profile-gc literally makes to program not do anything due to slow down
> is there any way to profile-gc in a faster fashion?
> Is there a native function which will return the memory usage of my
If it's total GC memory only you are interested in, then try the D
runtime switch for the GC: --DRT-gcopt=profile:1
This will print out a summary of GC usage at the end of your program,
and shouldn't significantly affect runtime.
> Is there a function to return sizes of AAs and even class instances ?
Class instances have a compiler-defined size. Try
This is the compile-time size of that specific type. If you have a class
instance, and you want the actual class size, in the case of a derived
instance, you may retrieve that using
Note also that this is not necessarily the size consumed from the GC! If
you want *that* size, you need to use GC.sizeof(cast(void*)object) (you
were almost correct, what you did was get the GC size of the *class
reference* which is really a pointer, and really lives on the stack,
hence the 0).
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