[Mono-devel-list] Memory management for long running processes (desc-heap profiler)

[Ben Maurer]

On Tue, 2005-03-29 at 22:14 +0100, Alex Chudnovsky wrote:
> Ben Maurer wrote:
> 
> >Does the heapsize = xxxxx bytes grow without bound (ie, does it leak?).
> >If not, than managed memory is *not* your issue.
> >  
> >
> It appears I have located at least one place in software that results in 
> huge memory consumption
> and it appears to be close to what I got reported by users of my 
> software. Here is GC printout:
> 
> --------------------------------------------------------------------------------
> Initiating full world-stop collection 65 after 32676644 allocd bytes
> --> Marking for collection 65 after 32676644 allocd bytes + 618028 
> wasted bytes
> Collection 64 finished ---> heapsize = 56414208 bytes
> World-stopped marking took 50 msecs
> Complete collection took 80 msecs
> Initiating full world-stop collection 66 after 29583120 allocd bytes
> --> Marking for collection 66 after 29583120 allocd bytes + 516520 
> wasted bytes
> Collection 65 finished ---> heapsize = 56414208 bytes
> World-stopped marking took 60 msecs
> Complete collection took 80 msecs
> Increasing heap size by 8388608 after 10701492 allocated bytes
> Initiating full world-stop collection 67 after 26805540 allocd bytes
> --> Marking for collection 67 after 26805540 allocd bytes + 662452 
> wasted bytes
> Collection 66 finished ---> heapsize = 64802816 bytes
> World-stopped marking took 50 msecs
> Complete collection took 70 msecs
> Increasing heap size by 58474496 after 0 allocated bytes 
> <------------------ PROBLEM
> Initiating full world-stop collection 68 after 42697296 allocd bytes
> --> Marking for collection 68 after 42697296 allocd bytes + 36000 wasted 
> bytes
> Collection 67 finished ---> heapsize = 123277312 bytes
> World-stopped marking took 60 msecs
> Complete collection took 80 msecs
> Increasing heap size by 87617536 after 0 allocated bytes 
> <------------------ PROBLEM
> Initiating full world-stop collection 69 after 71215316 allocd bytes
> --> Marking for collection 69 after 71215316 allocd bytes + 4580 wasted 
> bytes
> Collection 68 finished ---> heapsize = 210894848 bytes
> World-stopped marking took 60 msecs
> Complete collection took 70 msecs
> Increasing heap size by 87617536 after 0 allocated bytes 
> <------------------ PROBLEM
> Increasing heap size by 52305920 after 70980096 allocated bytes
> --------------------------------------------------------------------------
> 
> Note last few iterations -- memory usage grown BIG time all of a sudden, 
> and what I find
> interesting is that GC says that it increased heap after allocating 0 
> (zero) bytes!!! 8-O

Maybe right after a gc somebody is trying to allocate LOTS of memory?

> 
> I am digging in now to try to get more information about where in my 
> software exactly it happens and
> any possible explanations to whether what happens is expected (you never 
> know, maybe my
> code tried to allocated gigabyte of RAM?)

Are you making allocations larger than say 10 mb. Doing that is a really
bad idea today.

-- Ben