[Mono-dev] [Mono-gc-list] Mono memory problems!

David Wolinsky davidiw at ufl.edu
Wed Jul 18 13:54:49 EDT 2007


That case leaks as well.

Regards,
David

Miguel de Icaza wrote:
>> namespace Ipop {
>>   public class IPOP_Common {
>>     public static void Main() {
>>       AutoResetEvent re = null;
>>       while(true) {
>>         re = new AutoResetEvent(false);
>>         re.Close();
>>       }
>>     }
>>   }
>> }
>>
>> blows up memory
>>     
>
> That depends on the finalizer to run to release memory from the
> unmanaged side, since AutoResetEvent implements IDisposable you should
> use it like this:
>
> 	using (re = AutoResetEvent (false)) {	
> 		...
>
> Miguel
>   
>> whereas ...
>>
>> using System.Security.Cryptography;
>> using System;
>>
>> namespace Ipop {
>>   public class IPOP_Common {
>>     public static void Main() {
>>       RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
>>       while(true) {
>>         byte[] key = new byte[1024];
>>         rng.GetBytes(key);
>>       }
>>     }
>>   }
>> }
>>
>> This doesn't.
>>
>> David Wolinsky wrote:
>>     
>>> We run this software on system where memory is a concern.  The data that 
>>> we presented is our test case system that has 50 nodes all running in 
>>> the same mono process.  We run only a single node at each site which 
>>> initially starts at ~15 MB, we've seen it swell to well over 300 MBs in 
>>> a period of less than a week.  Since this must be used in production 
>>> environments and is meant to be extremely lightweight we can forgive a 
>>> small memory portion like 15 MB, since it has relatively no processing 
>>> overhead, but at over 300 MBs our processes are often stopped by the 
>>> remote admin and we are told to clean up the problem.
>>>
>>> Since this seems to be a problem of using a non-compacting gc, do you 
>>> know where the compacting gc is, so that we could at least test it out.  
>>> I searched the SVN and found no clues of it.
>>>
>>> Also, I should correct myself, the results for memory consumption were 
>>> not directly related to the test that grows at 25kB/sec.  I found this 
>>> out after posting the data, I am running heap-shot right now with the 
>>> correct test and it has grown 100MB in less than 1 hour.
>>>
>>> Regards,
>>> David
>>>
>>>
>>>
>>> Alan McGovern wrote:
>>>   
>>>       
>>>> Well, after 12 hours at a consistent 25kB/sec, you'd expect to have 
>>>> over 1 gig of memory allocated. As you don't, i think what you're 
>>>> seeing is just 'normal usage' for the non-compacting GC that mono 
>>>> uses. I have a similar app which uses sockets extensively (50-150 
>>>> simultaneous connections)  and i can assure you that memory usage 
>>>> doesn't get unbearably large. It'd be interesting to see the logs but 
>>>> i don't think there's much to be worried about.
>>>>
>>>> Alan.
>>>>
>>>> On 7/18/07, *David Wolinsky* <davidiw at ufl.edu 
>>>> <mailto:davidiw at ufl.edu>> wrote:
>>>>
>>>>     Initially 45 MB, 12 hours later 147 MB
>>>>
>>>>     Another developer has the heap-shot logs, I'll post those as soon as
>>>>     possible.
>>>>
>>>>     David
>>>>
>>>>     Alan McGovern wrote:
>>>>     > Could you post up the detailed stats from heapshot? After the 12
>>>>     hour
>>>>     > run, how much memory are you using? Are we talking in the gigabyte
>>>>     > range, or megabyte range?
>>>>     >
>>>>     > Alan.
>>>>     >
>>>>     > On 7/18/07, *David Wolinsky* <davidiw at ufl.edu
>>>>     <mailto:davidiw at ufl.edu>
>>>>     > <mailto:davidiw at ufl.edu <mailto:davidiw at ufl.edu>>> wrote:
>>>>     >
>>>>     >     My lab works on a peer-to-peer network overlay and we've noticed
>>>>     >     recently significant memory issues.  Some background...
>>>>     >
>>>>     >     This application is constantly creating new objects and shortly
>>>>     >     thereafter deleting (removing reference to) them
>>>>     >     Using a sample run with 150 threads running...
>>>>     >     Mono on Linux has a growth rate of ~25 KB per second with a
>>>>     base
>>>>     >     of 50MB
>>>>     >     (y = 25K *x + 50M)
>>>>     >     .NET on Windows stabilizes at 35 MB
>>>>     >
>>>>     >     We ran heap-shot with Linux and found that in a 12 hour
>>>>     period it
>>>>     >     reported this...
>>>>     >     start:
>>>>     >     objects: 58,823
>>>>     >     heap memory: 6,838,426 bytes
>>>>     >
>>>>     >     end:
>>>>     >     objects: 59,925
>>>>     >     heap memory: 6,862,336
>>>>     >
>>>>     >     We have run mono with GC_MAXIMUM_HEAP_SIZE and the memory size
>>>>     >     (RES) got
>>>>     >     significantly bigger than it.
>>>>     >
>>>>     >     I have searched for the Compacting GC with no luck, we would
>>>>     >     really like
>>>>     >     to see if it would help our problem.
>>>>     >
>>>>     >     The only operating system resources we're using are Sockets, but
>>>>     >     we use
>>>>     >     them VERY heavily!
>>>>     >
>>>>     >     If anyone has any suggestions, we'd be open to test out
>>>>     anything
>>>>     >     at this
>>>>     >     point!
>>>>     >
>>>>     >     We are leaning towards an issue in unmanaged memory and
>>>>     possibly a bug
>>>>     >     in mono.
>>>>     >
>>>>     >     Best regards,
>>>>     >     David
>>>>     >
>>>>     >
>>>>     >     ps, I fwded this to gc and devel list because gc list looks
>>>>     quite
>>>>     >     dead.... sorry for the duplication
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>>>>     >
>>>>     >
>>>>
>>>>
>>>>     
>>>>         
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