Running the JCK by distributing the tests to be run in parallel to multiple agents on the same machine, as many agents as there are cpus/cores, sometimes fails the vm/jvmti tests due to connection refused. This typically only happens with high load on Linux x86.

A typical error message is

----------messages:(1/1583)----------
command: com.sun.jck.lib.ExecJCKTestOtherJVMCmd LD_LIBRARY_PATH=/localhome/tendril4.2/work/install/jck-60b-binaries/JCK-runtime-6b/lib/native DISPLAY=sthqa62:13 HOME= TENDRIL_TASK_ID=2650046 TENDRIL_RUN_ID=24699457 TENDRIL_REQUEST_ID=5520519 TMP=/localhome/tendril4.2/work/install/echelon2_main/echelon2_main/results/tmp/jck_tmp TEMP=/localhome/tendril4.2/work/install/echelon2_main/echelon2_main/results/tmp/jck_tmp /localhome/tendril4.2/work/install/jrockit_R28.0.0-656_debug_1.6.0/jrockit_debug-jdk1.6.0_17/bin/java -Djava.home=/localhome/tendril4.2/work/install/jrockit_R28.0.0-656_debug_1.6.0/jrockit_debug-jdk1.6.0_17/jre -Djava.ext.dirs=/localhome/tendril4.2/work/install/jrockit_R28.0.0-656_debug_1.6.0/jrockit_debug-jdk1.6.0_17/jre/lib/ext:/localhome/tendril4.2/work/install/jck-60b-binaries/JCK-runtime-6b/lib/extensions -XX:+CrashOnAssert -XX:-WaitOnCrash -Xsanity:livemap=debug -XXdumpfullstate -Djava.io.tmpdir=/localhome/tendril4.2/work/install/echelon2_main/echelon2_main/results/tmp/jck_tmp -XX:+FailOverToOldVerifier -Xverify -Duser.language=US -Xmx128m -Xfuture -cp /localhome/tendril4.2/work/install/jck-60b-binaries/JCK-runtime-6b/classes:/localhome/tendril4.2/work/install/jrockit_R28.0.0-656_debug_1.6.0/jrockit_debug-jdk1.6.0_17/lib/tools.jar -Djava.security.policy=/localhome/tendril4.2/work/install/jck-60b-binaries/JCK-runtime-6b/lib/jck.policy javasoft.sqe.tests.vm.jvmti.mcen001.mcen00101.mcen00101 -platform.jvmtiLivePhaseSupported true -attachClassName javasoft.sqe.jck.lib.attach.JVMTIAttachConnector -jvmtiAgentName jckjvmti -jvmtiAgentOpts mcen00101
----------out1:(0/0)----------
----------out2:(18/1413)----------
Cannot attach to JVM with id=29196 , unexpected exception thrown: javasoft.sqe.jck.lib.attach.AttachConnector$AttachException: Cannot attach to the Java virtual machine
javasoft.sqe.jck.lib.attach.AttachConnector$AttachException: Cannot attach to the Java virtual machine
at javasoft.sqe.jck.lib.attach.JVMTIAttachConnector.attach(JVMTIAttachConnector.java:42)
at javasoft.sqe.jck.lib.jvmti.Agent.attachAndLoadNativeAgent(Agent.java:282)
at javasoft.sqe.jck.lib.jvmti.Agent.attach(Agent.java:77)
at javasoft.sqe.tests.vm.jvmti.mcen001.mcen00101.mcen00101.run(mcen00101.java:30)
at javasoft.sqe.tests.vm.jvmti.mcen001.mcen00101.mcen00101.main(mcen00101.java:20)
Caused by: java.io.IOException: Connection refused
at sun.tools.attach.LinuxVirtualMachine.connect(Native Method)
at sun.tools.attach.LinuxVirtualMachine.(LinuxVirtualMachine.java:100)
at sun.tools.attach.LinuxAttachProvider.attachVirtualMachine(LinuxAttachProvider.java:46)
at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:195)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javasoft.sqe.jck.lib.attach.JVMTIAttachConnector.attach(JVMTIAttachConnector.java:39)
... 4 more
result: Failed. test failed

test result: Failed. test failed
Need reproducible test case. Please send agent (or agent src) and invocation instructions that produce connection refusal. Please also include affected JVM and OS version strings.