[infinispan-dev] ISPN-863 - Thoughts / Questions

Galder Zamarreño galder at redhat.com
Thu Jan 20 03:38:43 EST 2011 

On Jan 19, 2011, at 1:47 PM, david marion wrote:

>  
>   It was my problem. If -1 is set for maxEntries, then I am creating a BoundedConcurrentHashMap with a size of Integer.MAX_VALUE. Then when I ran the tests all of them ran out of memory. I should have looked at the stack trace a little more closely. I am going to have to put logic in so that the maximum capacity is determined by the amount of free memory when the cache is created. Previously, if -1 was set for maxEntries, a ConcurrentHashMap was created with maximum capacity of Integer.MAX_VALUE. I have not looked at the code, but my guess is that it works because it grows over time and does not pre-allocate all structures ahead of time.

Hmmm, that sounds odd. Maybe you wanna build a test to show the exact differences and see if too much is being allocated on startup?

> Any thoughts on logic for determining maximum capacity at creation time? 

A percentage of the available free memory? 40% by default? You have to accomodate for the other apps running on the same JVM, so we shouldn't be too aggressive by default.

>  
> > From: galder at redhat.com
> > Date: Wed, 19 Jan 2011 10:32:42 +0100
> > To: infinispan-dev at lists.jboss.org
> > Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions
> > 
> > Out of curiosity, what is a code problem on your side? Or a set up issue?
> > 
> > On Jan 19, 2011, at 4:29 AM, david marion wrote:
> > 
> > > Disregard, I found the issue. Sorry for the spam.
> > > 
> > > > From: dlmarion at hotmail.com
> > > > To: infinispan-dev at lists.jboss.org
> > > > Date: Tue, 18 Jan 2011 20:39:21 -0500
> > > > Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions
> > > > 
> > > > Hah, might be because the POM is configured to run tests in parallel with a
> > > > max heap size of 1GB. Can someone update
> > > > http://community.jboss.org/wiki/ParallelTestSuite or
> > > > http://community.jboss.org/wiki/InfinispanQuickStartGuideforDevelopers#Testi
> > > > ng with instructions on how to run test serially (I didn’t find anything wrt
> > > > Maven surefire plugin)? Thanks
> > > > 
> > > > -----Original Message-----
> > > > From: infinispan-dev-bounces at lists.jboss.org
> > > > [mailto:infinispan-dev-bounces at lists.jboss.org] On Behalf Of Galder
> > > > Zamarreño
> > > > Sent: Tuesday, January 18, 2011 6:12 AM
> > > > To: infinispan -Dev List
> > > > Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions
> > > > 
> > > > Hmmm, try increasing -Xmx? Start with -XX:+HeapDumpOnOutOfMemoryError
> > > > -XX:HeapDumpPath=/tmp/java_heap and inspect the dump with Eclipse MAT?...
> > > > 
> > > > On Jan 17, 2011, at 4:51 PM, david marion wrote:
> > > > 
> > > > > same result.
> > > > > 
> > > > > Date: Mon, 17 Jan 2011 11:54:15 -0300
> > > > > From: vblagoje at redhat.com
> > > > > To: infinispan-dev at lists.jboss.org
> > > > > Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions
> > > > > 
> > > > > Its easier to run everything from command line for two reason I can think
> > > > of:
> > > > > - everyone has same env to compare results with you
> > > > > - it is all ready to go
> > > > > 
> > > > > See http://community.jboss.org/wiki/InfinispanandMaven
> > > > > 
> > > > > On 11-01-17 11:38 AM, Dave wrote:
> > > > > All,
> > > > > 
> > > > > I am trying to test some changes that I made using Eclipse and the TestNG
> > > > plugin. I am not familiar with TestNG. Are there any settings that I should
> > > > make? Any ideas?
> > > > > 
> > > > > java.lang.OutOfMemoryError: Java heap space
> > > > > at
> > > > org.infinispan.util.concurrent.BoundedConcurrentHashMap$HashEntry.newArray(B
> > > > oundedConcurrentHashMap.java:295)
> > > > > at
> > > > org.infinispan.util.concurrent.BoundedConcurrentHashMap$Segment.<init>(Bound
> > > > edConcurrentHashMap.java:898)
> > > > > at
> > > > org.infinispan.util.concurrent.BoundedConcurrentHashMap.<init>(BoundedConcur
> > > > rentHashMap.java:1367)
> > > > > at
> > > > org.infinispan.container.DefaultDataContainer.<init>(DefaultDataContainer.ja
> > > > va:78)
> > > > > at
> > > > org.infinispan.container.DefaultDataContainer.<init>(DefaultDataContainer.ja
> > > > va:47)
> > > > > at
> > > > org.infinispan.container.DefaultDataContainer.unBoundedDataContainer(Default
> > > > DataContainer.java:93)
> > > > > at
> > > > org.infinispan.factories.DataContainerFactory.construct(DataContainerFactory
> > > > .java:53)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
> > > > ractComponentRegistry.java:315)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
> > > > tractComponentRegistry.java:251)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
> > > > ies(AbstractComponentRegistry.java:840)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:225)
> > > > > at
> > > > org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
> > > > ry.java:120)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:192)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
> > > > ractComponentRegistry.java:323)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
> > > > tractComponentRegistry.java:251)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
> > > > ies(AbstractComponentRegistry.java:840)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:225)
> > > > > at
> > > > org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
> > > > ry.java:120)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:192)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
> > > > ractComponentRegistry.java:323)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
> > > > tractComponentRegistry.java:251)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
> > > > ies(AbstractComponentRegistry.java:840)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:225)
> > > > > at
> > > > org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
> > > > ry.java:120)
> > > > > at
> > > > org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
> > > > tComponentRegistry.java:192)
> > > > > at
> > > > org.infinispan.factories.InternalCacheFactory.bootstrap(InternalCacheFactory
> > > > .java:92)
> > > > > at
> > > > org.infinispan.factories.InternalCacheFactory.createAndWire(InternalCacheFac
> > > > tory.java:78)
> > > > > at
> > > > org.infinispan.factories.InternalCacheFactory.createCache(InternalCacheFacto
> > > > ry.java:62)
> > > > > at
> > > > org.infinispan.manager.DefaultCacheManager.createCache(DefaultCacheManager.j
> > > > ava:510)
> > > > > at
> > > > org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java
> > > > :440)
> > > > > at
> > > > org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java
> > > > :409)
> > > > > at
> > > > org.infinispan.config.ConfigurationValidationTest.testDefaultMemoryGuardConf
> > > > iguration(ConfigurationValidationTest.java:100)
> > > > > 
> > > > > 
> > > > > 
> > > > > -----Original Message-----
> > > > > From: infinispan-dev-bounces at lists.jboss.org
> > > > [mailto:infinispan-dev-bounces at lists.jboss.org] On Behalf Of Vladimir
> > > > Blagojevic
> > > > > Sent: Friday, January 14, 2011 11:05 AM
> > > > > To: infinispan -Dev List
> > > > > Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions
> > > > > 
> > > > > Hey David,
> > > > > 
> > > > > First of all kudos for taking on such a non-trivial task!
> > > > > 
> > > > > On 11-01-14 12:22 AM, david marion wrote:
> > > > > 1. Modify configuration in some way so that the following can be
> > > > specified:
> > > > > a. The percentage value of used JVM memory (i.e. 95) at which
> > > > entries should be evicted to try and avoid an OOM error.
> > > > > b. The number of items that should be evicted when memory reaches
> > > > this threshold
> > > > > 2. Modify LRU and LIRS Eviction class so that the accessQueue member
> > > > can be accessed by the new Eviction class so that two access queues don’t
> > > > have to be maintained.
> > > > > 3. Create a new Eviction class, a subclass of LIRS, where the
> > > > accessQueue is used from the Eviction strategy the user specifies and the
> > > > for loop in the execute method is exited when the evicted set equals value
> > > > from 1.b above.
> > > > > 4. Modify DataContainerFactory.construct() to call
> > > > DefaultDataContainer.boundedDataContainer() regardless of eviction policy.
> > > > This will always create a BoundedConcurrentHashMap
> > > > > 
> > > > > I don't think you have to extend LRU and LIRS, as long as you implement
> > > > EvictionPolicy you are fullfilling the contract. What extending LRU and LIRS
> > > > can do is give you some order in selecting proper elements for eviction. I
> > > > think the precise technical term in research literature is "eviction
> > > > precision". 
> > > > > 
> > > > > 
> > > > > 1. 
> > > > > 2. Create an instance of the new Eviction class in each segment.
> > > > > 3. Modify BoundedConcurrentHashMap.Segment put and replace methods
> > > > such that when new values are going to be put into the Segment, the memory
> > > > usage is checked and the execute method is called on the new Eviction class.
> > > > > 
> > > > > Sounds right!
> > > > > 
> > > > > 
> > > > > 1. 
> > > > > 
> > > > > Questions:
> > > > > 
> > > > > 1. What are the implications of using a BoundedConcurrentHashMap
> > > > instead of a ConcurrentHashMap when maxEntries is set to -1?
> > > > > 
> > > > > I think none except you turn on eviction by using
> > > > BoundedConcurrentHashMap.
> > > > > 
> > > > > 
> > > > > 1. 
> > > > > 
> > > > > Thoughts
> > > > > 
> > > > > 1. This will not guarantee that an OOM error does not occur. It will
> > > > attempt to guard against an OOM caused by putting new values into the cache.
> > > > This will probably be more effective when the cache is being used in
> > > > client/server mode, and less effective when used in embedded mode as to
> > > > other code running in the JVM.
> > > > > 
> > > > > 
> > > > > -- Dave Marion
> > > > > 
> > > > > 
> > > > > Cheers,
> > > > > Vladimir
> > > > > 
> > > > > _______________________________________________
> > > > > infinispan-dev mailing list
> > > > > 
> > > > > infinispan-dev at lists.jboss.org
> > > > > https://lists.jboss.org/mailman/listinfo/infinispan-dev
> > > > > 
> > > > > 
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> > > > 
> > > > --
> > > > Galder Zamarreño
> > > > Sr. Software Engineer
> > > > Infinispan, JBoss Cache
> > > > 
> > > > 
> > > > _______________________________________________
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> > > > infinispan-dev at lists.jboss.org
> > > > https://lists.jboss.org/mailman/listinfo/infinispan-dev
> > > > 
> > > > 
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> > 
> > --
> > Galder Zamarreño
> > Sr. Software Engineer
> > Infinispan, JBoss Cache
> > 
> > 
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--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache

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