OK, I will check it out while in the different states. However, I am not
sure there is actually a leak. What I'm seeing is that memory usage seems
to plateau after a certain number of clients, rather than continuing to
increase linearly. I'm trying to understand why this happens.
Thanks,
Eric
On Thu, Jun 28, 2012 at 9:57 AM, Oleksiy Stashok <oleksiy.stashok_at_oracle.com
> wrote:
> Hi Eric,
>
> I think you're on the right way.
> See inline...
>
>
> On 06/28/2012 04:40 AM, Eric Luong wrote:
>
> Any suggestions on what to look for with jmap/jhat? I'm unfamiliar with
> the tools. When I run jhat on a heap dump, it comes up with a fair number
> of warnings -- "Failed to resolve object id [some id]" and "Failed to
> resolve object id [some id] for field value (signature L)". Not sure what
> these mean. It might be worth mentioning that I had to use -F on jmap;
> without it, I get the "target process is not responding".
>
> That's correct.
>
>
>
> Just looking at this snapshot (which is not near the plateau I described),
> it seems the class with the largest total size is "class [C" which is
> obviously not a useful class name.
>
> It's character arrays.
> I just took snapshot w/ jmap and opened in jhat.
> In the browser I clicked "Heap histogram", now I see types sorted by
> number of instances and memory consumption.
>
> When you investigate the problem, pls. take a snapshot when issue occurs
> and check the heap histogram. Most probably the problematic object (which
> leaks) would be on the top of the list.
>
>
>
> Does that mean it is some anonymous class? Exploring it further, it only
> lists Object as its superclass. There are several other such nameless
> classes. Other information for these classes (ClassLoader, Signers,
> Protection Domain) are all null. Other classes that seem to consume the
> majority of memory are HashMap, HashMapEntry and related classes.
>
> Most of the time char[] is at the top of the list, different collections
> like HashMap also.
> Pls. take a snapshot when the memory issue occurs and check the heap
> histogram, may be you'll find some suspicious object on the top. If not -
> you can share the snapshot file, I can try to help.
>
>
>
> Can you suggest how to approach this using jmap/jhat, and if those
> warnings I received are of any significance?
>
> I also see warnings from jhat, but IMO it's still ok.
>
> You can also check another profiler tools like the one Chris suggested
> (visual vm).
>
> Thanks.
>
> WBR,
> Alexey.
>
>
> Then I will proceed with checking out different memory state snapshots.
>
> Thanks for your help,
>
> Eric
>
> On Mon, Jun 25, 2012 at 6:37 AM, Oleksiy Stashok <
> oleksiy.stashok_at_oracle.com> wrote:
>
>> Hi Eric,
>>
>> it would be great if you can monitor the memory usage using some profiler
>> tool or jmap/jhat and give us more details on objects (object types), which
>> consume memory. You can take several memory state snapshots like initial,
>> 1000 clients connected, 2000 clients connected, 3000 clients connected, so
>> we can see the dynamics and figure out the problem (if there is any).
>>
>> Thanks.
>>
>> WBR,
>> Alexey.
>>
>>
>> On 06/23/2012 04:48 AM, Eric Luong wrote:
>>
>>> Hello,
>>>
>>> I've been testing Grizzly in Glassfish 3.1 by simulating a load of
>>> thousands of clients using long polling. I found what appears to be a
>>> bottleneck. As more clients are added, the memory usage of the server
>>> increases. However, after a certain point (2000 clients in my case, but I
>>> expect it would depend on hardware) the usage seems to taper off and
>>> plateau.
>>>
>>> I have been trying to figure out why the memory usage plateaus. Can
>>> anyone offer some insights, or suggest a way to investigate further?
>>>
>>> Thank-you!
>>>
>>> Eric
>>>
>>
>>
>>
>
>
>