RFR(s): 8243451: nsk.share.jdi.Debugee.isJFR_active() is incorrect and corresponsing logic seems to be broken

[Fairoz Matte]

Hi Serguei,

Thanks for the clarifications,
I have incorporated the 2nd suggestion, below is the webrev,
http://cr.openjdk.java.net/~fmatte/8243451/webrev.09/

Thanks,
Fairoz

From: Serguei Spitsyn 
Sent: Monday, June 8, 2020 10:34 PM
To: Fairoz Matte <fairoz.matte at oracle.com>; Erik Gahlin <erik.gahlin at oracle.com>
Cc: serviceability-dev at openjdk.java.net
Subject: Re: RFR(s): 8243451: nsk.share.jdi.Debugee.isJFR_active() is incorrect and corresponsing logic seems to be broken

Hi Fairoz,


On 6/8/20 02:08, mailto:serguei.spitsyn at oracle.com wrote:
Hi Fairoz,

There are two different isJFRActive() methods, one is on debuggee side and another on the debugger side.
The one on debuggee side is better to keep in Debuggee.java (where it was before) instead of moving it to HeapwalkingDebuggee.java.
It is okay to keep the call to it in the HeapwalkingDebuggee.java.

Please, skip this suggestion as Debugger.java is not one of supers of HeapwalkingDebuggee.java as I've assumed.

Thanks,
Serguei


+    protected boolean isJFRActive() {
+        boolean isJFRActive = false;
+        ReferenceType referenceType = debuggee.classByName("nsk.share.jdi.HeapwalkingDebuggee");
+        if (referenceType == null)
+           throw new RuntimeException("Debugeee is not initialized yet");
+
+        Field isJFRActiveFld = referenceType.fieldByName("isJFRActive");
+        isJFRActive = ((BooleanValue)referenceType.getValue(isJFRActiveFld)).value();
+        return isJFRActive;
     }
It is better to remove the line:
+        boolean isJFRActive = false;
and just change this one:
+        boolean isJFRActive = ((BooleanValue)referenceType.getValue(isJFRActiveFld)).value();

Otherwise, it looks good to me.
I hope, it really works now.

Thanks,
Serguei

On 6/8/20 00:26, Fairoz Matte wrote:
Hi Serguei, Erik,
 
Thanks for the reviews,
Below webrev contains the suggested changes, 
http://cr.openjdk.java.net/~fmatte/8243451/webrev.08/
 
The only thing I couldn’t do is to keep the local copy of isJFRActive() in HeapwalkingDebugger, 
The method is called in debugee code.
In debugger, we have access to debugee before test started or after test completes.
isJFRActive() method need to be executed during the test execution. Hence I didn’t find place to initialize and cannot make local copy.
 
Thanks,
Fairoz
 
From: Serguei Spitsyn 
Sent: Tuesday, June 2, 2020 7:57 AM
To: Fairoz Matte mailto:fairoz.matte at oracle.com; Erik Gahlin mailto:erik.gahlin at oracle.com
Cc: mailto:serviceability-dev at openjdk.java.net
Subject: Re: RFR(s): 8243451: nsk.share.jdi.Debugee.isJFR_active() is incorrect and corresponsing logic seems to be broken
 
On 6/1/20 12:30, mailto:serguei.spitsyn at oracle.com wrote:
Hi Fairoz,

It looks okay in general.
But I'm not sure this check is going to work.
The problem is the HeapwalkingDebuggee.useStrictCheck method is invoked in the
context of the HeapwalkingDebugger process, not the HeapwalkingDebuggee process.

Probably, you wanted to get this bit of information from the Debuggee process.
The debuggee has to evaluate it itself and store in some field.
The debugger should use the JDI to get this value from the debuggee.

Thanks,
Serguei

I'm not sure, what exactly you wanted to do here.
It can occasionally work for you as long as both processes are run with the same options.

Thanks,
Serguei


On 6/1/20 08:52, Fairoz Matte wrote:
Hi Erik,
 
Thanks for the review, below is the updated webrev.
http://cr.openjdk.java.net/~fmatte/8243451/webrev.02/
 
Thanks,
Fairoz
 
-----Original Message-----
From: Erik Gahlin
Sent: Monday, June 1, 2020 4:26 PM
To: Fairoz Matte mailto:fairoz.matte at oracle.com
Cc: mailto:serviceability-dev at openjdk.java.net
Subject: Re: RFR(s): 8243451: nsk.share.jdi.Debugee.isJFR_active() is incorrect
and corresponsing logic seems to be broken
 
Hi Fairoz,
 
What I think you need to do is something like this:
 
         if (className.equals("java.lang.Thread")) {
             return !isJfrInitialized();
         }
 
...
 
     private static boolean isJfrInitialized() {
         try {
             Class<?> clazz = Class.forName("jdk.jfr.FlightRecorder");
             Method method = clazz.getDeclaredMethod("isInitialized",
new Class[0]);
             return (boolean) method.invoke(null, new Object[0]);
         } catch (Exception e) {
             return false;
         }
     }
 
Erik
 
On 2020-06-01 12:30, Fairoz Matte wrote:
Hi Erik,
 
Thanks for your quick response,
Below is the updated webrev to handle if jfr module is not present
http://cr.openjdk.java.net/~fmatte/8243451/webrev.01/
 
Thanks,
Fairoz
 
-----Original Message-----
From: Erik Gahlin
Sent: Monday, June 1, 2020 2:31 PM
To: Fairoz Matte mailto:fairoz.matte at oracle.com
Cc: mailto:serviceability-dev at openjdk.java.net
Subject: Re: RFR(s): 8243451: nsk.share.jdi.Debugee.isJFR_active() is
incorrect and corresponsing logic seems to be broken
 
Hi Fairoz,
 
If the test needs to run with builds where the JFR module is not
present(?), you need to do the check using reflection.
 
If not, looks good.
 
Erik
 
On 1 Jun 2020, at 10:27, Fairoz Matte mailto:fairoz.matte at oracle.com wrote:
 
Hi,
 
Please review this small test infra change to identify at runtime
the JFR is
active or not.
JBS - https://bugs.openjdk.java.net/browse/JDK-8243451
Webrev - http://cr.openjdk.java.net/~fmatte/8243451/webrev.00/
 
Thanks,
Fairoz