Okay then.
Thanks, David for reminding this!
Gary,
I guess, you still have a discussion with Chris, so it is not ready for
push yet.
Thanks,
Serguei
On 8/6/18 15:15, David Holmes wrote:
On 7/08/2018 4:51 AM, serguei.spit...@oracle.com wrote:
My understanding is that volatile is to prevent compiler optimizations.
Java volatile is purely about establishing orderings within the Java
memory model. It is needed only for lock-free access to variables
shared across threads.
Cheers,
David
This has to the exact case where it is needed.
Thanks,
Serguei
On 8/6/18 11:46, Gary Adams wrote:
I used the same declaration used for "instruction" variable,
which was already being used for getValue() calls.
I think we would want volatile if this was thread to thread
communication, but these variables are being used
for interprocess communication between the debugger and a
debuggee process. There are no reader/writer race conditions
here.
On 8/6/18, 1:36 PM, serguei.spit...@oracle.com wrote:
Hi Gary,
I was going to sponsor this but wanted to look at the latest webrev
first.
And found this:
44 static int testCase = -1;
Should it be declared as volatile?
Thanks,
Serguei
On 8/6/18 05:27, Gary Adams wrote:
I'll need a sponsor for the patch attached.
On 8/6/18, 7:16 AM, Gary Adams wrote:
On 8/3/18, 6:38 PM, Chris Plummer wrote:
Hi Gary,
Overall it looks good.
Is the EventHandler.isDisconnected() check needed?
This just follows the pattern used in other calls to setValue.
No point in attempting the operation, if you know the
connection was lost. An exception at this point could
be misleading, if some other error has already occurred.
In resume008a.java you removed a lot of empty lines. In some
places it's fine, but the lines at 132 and 134 should have
remained. Also, for the ones that were ok to remove, I don't see
you doing the same thing in the other files. I think probably
it's best to be consistent, and for this webrev probably best
not to do them since it distracts too much from the important
changes.
The original bug was reported against resume008, so more time was
spent in that
particular test, including some line wrapping changes. I will
restore the blank lines
you mentioned before producing a final patch. The other tests had
observed failures
also during testing. Applying the same change fixed those
failures as well.
Seems like there is a lot of abstraction that could have been
done with these tests to share a lot of code, but since so far
that hasn't been done, probably not a good idea to start doing
that with this fix. Do you think it's worth filing an
enhancement request for?
Reformatting or refactoring these older tests would be at best a P5.
I don't think it's worth filing a bug, but as we fix bugs in
these test it's
worth some minimal amount of cleanup while we are in the code.
thanks,
Chris
On 8/3/18 11:04 AM, Gary Adams wrote:
Here is an updated webrev with the alternate solution
implemented for
resume 1 to 10. The debugger sets testCase variable in the
debuggee
when each test case completes in the debugger. By having the
debuggee
wait for the debugger to complete with test case 0, it avoids
the interference
that occurs by proceeding to the breakpoint set in
MethodForCommunication
before the debugger has compared expected suspend counts.
Webrev:
http://cr.openjdk.java.net/~gadams/8170089/webrev.01/index.html
On 7/17/18, 11:33 AM, Gary Adams wrote:
A race condition exists between the debugger and the debuggee.
The first test thread is started with SUSPEND_NONE policy set.
While processing the thread start event the debugger captures
an initial set of thread suspend counts and resumes the
debuggee vm. If the debuggee advances quickly it reaches
the breakpoint set for methodForCommunication. Since the
breakpoint
carries with it SUSPEND_ALL policy, when the debugger captures
a second
set of suspend counts, it will not match the expected counts for
a SUSPEND_NONE scenario.
The proposed fix introduces a yield in the debuggee test
thread run method
to allow the debugger to get the expected sampled values.
Issue: https://bugs.openjdk.java.net/browse/JDK-8170089
Webrev: http://cr.openjdk.java.net/~gadams/8170089/webrev.00/
test/hotspot/jtreg/vmTestbase/nsk/share/jdi/TestDebuggerType1.java:
...
186 private void
setCommunicationBreakpoint(ReferenceType refType, String
methodName) {
187 Method method =
debuggee.methodByName(refType, methodName);
188 Location location = null;
189 try {
190 location =
method.allLineLocations().get(0);
191 } catch (AbsentInformationException e) {
192 throw new Failure(e);
193 }
194 bpRequest = debuggee.makeBreakpoint(location);
195
196 bpRequest.setSuspendPolicy(EventRequest.SUSPEND_ALL);
197 bpRequest.putProperty("number", "zero");
198 bpRequest.enable();
199
200 eventHandler.addListener(
201 new EventHandler.EventListener() {
202 public boolean eventReceived(Event
event) {
203 if (event instanceof
BreakpointEvent && bpRequest.equals(event.request())) {
204 synchronized(eventHandler) {
205 display("Received communication breakpoint event.");
206 bpCount++;
207 eventHandler.notifyAll();
208 }
209 return true;
210 }
211 return false;
212 }
213 }
214 );
215 }
test/hotspot/jtreg/vmTestbase/nsk/jdi/EventSet/resume/resume008.java:
...
140 display("......--> vm.suspend();");
141 vm.suspend();
142
143 display(" getting :
Map<String, Integer> suspendsCounts1");
144
145 Map<String, Integer> suspendsCounts1
= new HashMap<String, Integer>();
146 for (ThreadReference threadReference
: vm.allThreads()) {
147 suspendsCounts1.put(threadReference.name(),
threadReference.suspendCount());
148 }
149 display(suspendsCounts1.toString());
150
151 display(" eventSet.resume;");
152 eventSet.resume();
153
154 display(" getting :
Map<String, Integer> suspendsCounts2");
This is where the breakpoint is encountered before the second
set of suspend counts is acquired.
155 Map<String, Integer> suspendsCounts2
= new HashMap<String, Integer>();
156 for (ThreadReference threadReference
: vm.allThreads()) {
157 suspendsCounts2.put(threadReference.name(),
threadReference.suspendCount());
158 }
159 display(suspendsCounts2.toString());
