JVMTI VMObjectAlloc

[Lee Ming]

Hi, Thank you for your help,

I'll try to use BCI for the case

bhm

> Subject: Re: JVMTI VMObjectAlloc
> From: kelly.ohair at oracle.com
> Date: Fri, 10 Jun 2011 11:47:02 -0700
> CC: wonderer_101 at live.com; serviceability-dev at openjdk.java.net
> To: keith.mcguigan at oracle.com
> 
> 
> Read this carefully.
> 
> http://download.oracle.com/javase/7/docs/platform/jvmti/jvmti.html#VMObjectAlloc
> 
> 
> -kto
> 
> On Jun 10, 2011, at 11:28 AM, Keith McGuigan wrote:
> 
> > 
> > Forwarding to serviceability-dev (and Bcc'ing hotspot-runtime-dev off).
> > 
> > I personally don't see anything obviously wrong in the code you sent but it looks like you've only sent a small fragment of the code and the problem could well be somewhere else.  What is the output, and what do you expect?  Does it count 6, 600, or 6000, 60000 or what?  Is it even close?  What happens when you change the number of iterations in the java program?  Are you seeing any other threads calling allocation, and if so are you implementing the proper locking for your gdata?
> > 
> > --
> > - Keith
> > 
> > On Jun 10, 2011, at 1:58 PM, Lee Ming wrote:
> > 
> >> Hi,
> >> I'm doing some test with JVMTI VMObjectAlloc, and it seems like the callback cant catch object allocation properly .e.g: regardless how I tried to allocate new objects in Java program, the agent still report the same number of objects allocated.
> >> 
> >> This is the source code of the callback
> >> 
> >>    char *generic_name;
> >>    jvmtiThreadInfo info;
> >>    jvmtiError error;
> >> 
> >>    (void)memset(&info, 0, sizeof(info));
> >> 
> >>    error = (*jvmti)->GetClassSignature(jvmti, object_klass,&generic_name,NULL);
> >>    check_jvmti_error(jvmti, error, "can't get class name");
> >>    //printf(generic_name);
> >> 
> >>    gdata->object_size = gdata->object_size + size;
> >>    gdata->ccount++;
> >> 
> >>    stdout_message("%d.Object allocated, class: %s\tsize:%d\n",gdata->ccount,gener! ic_name,size);
> >>     printf("total size now is: %I64d\n",gdata->object_size);
> >> 
> >> 
> >>    error = (*jvmti)->GetThreadInfo(jvmti,thread, &info);
> >>    check_jvmti_error(jvmti, error, "can't get thread info");
> >>    printf("thread name:%s\n",info.name);
> >>    (*jvmti)->Deallocate(jvmti, (unsigned char *) info.name);
> >>    (*env)->DeleteLocalRef(env, info.thread_group);
> >>    (*env)->DeleteLocalRef(env, info.context_class_loader);
> >> 
> >> And the sample Java test file
> >>    public class Test {
> >> 
> >>    public static void main(String[] args){
> >> 
> >>            for(int i=0; i<10000;i++){
> >>        &nbs! p;           &n bsp;   Hello h1 = new Hello(1,2);
> >>                        Hello h2 = new Hello(3,4444);
> >>                        Hello h3 = new Hello(3,44);
> >>                        h1.w();
> >>                        h2.w();
> >>                        h3.w();
> >>                        //System.ou! t.println("alloc");
> >>            }
> >> 
> >>    }
> >> 
> >>   }
> >> 
> >> Please let's me know whether i have made any mistake
> >> 
> >> Thank you
> >> Bhm
> > 
> 
 		 	   		  
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