RFR: JDK-8152690: main thread does not have native thread name

Yasumasa Suenaga yasuenag at gmail.com
Sat Apr 23 13:24:38 UTC 2016


Hi Kumar,

Thank you for your comment!
I've fixed them and uploaded new webrev. Could you review again?

   http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.06/hotspot/
   http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.06/jdk/


Thanks,

Yasumasa


On 2016/04/23 1:14, Kumar Srinivasan wrote:
>
> Also a couple of minor suggestions:
>
> - * Set native thread name as possible.
> + * Set native thread name if possible.
>
>
> +      /*
> -       * We can clear pending exception because exception at this point
> -       * is not critical.
> +       */
>
> +      /*
> +       * Clear non critical pending exceptions at this point.
> +       */
>
> Thanks
> Kumar
>
>> Hi,
>>
>> This is in the wrong place:
>>
>> 1715     if ((*env)->ExceptionOccurred(env)) {
>> 1716       /*
>> 1717        * We can clear pending exception because exception at this point
>> 1718        * is not critical.
>> 1719        */
>> 1720       (*env)->ExceptionClear(env);
>> 1721     }
>>
>> This above needs to be after
>>  391     SetNativeThreadName(env, "main");
>>  392
>>
>> Here is why, supposing 1704 through 1711, returns a NULL,
>> but have also encountered an exception. In which case
>> the method SetNativeThreadName will return to the caller, as
>> if nothing has happened, because NULL_CHECK simply checks for NULL
>> and returns to the caller. This will cause the caller to enter
>> the VM with exceptions.
>>
>> Kumar
>>
>>
>> On 4/22/2016 5:11 AM, Yasumasa Suenaga wrote:
>>> Hi David,
>>>
>>>> I don't think we need to report the exception, but can just ignore it. Either way we have to clear the exception before continuing.
>>>
>>> I've fixed it in new webrev:
>>>
>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.05/hotspot/
>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.05/jdk/
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> On 2016/04/22 15:33, David Holmes wrote:
>>>> On 22/04/2016 1:36 PM, Yasumasa Suenaga wrote:
>>>>> Hi all,
>>>>>
>>>>> I have uploaded webrev.04 as below.
>>>>> Could you review again?
>>>>>
>>>>>  >  - hotspot:
>>>>>  > http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.04/hotspot/
>>>>
>>>> Looks fine.
>>>>
>>>>>  >
>>>>>  >  - jdk:
>>>>>  > http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.04/jdk/
>>>>
>>>> As per private email (but repeated here on the record) in java.c:
>>>>
>>>> 715     if ((*env)->ExceptionOccurred(env)) {
>>>> 1716       JLI_ReportExceptionDescription(env);
>>>> 1717     }
>>>>
>>>> I don't think we need to report the exception, but can just ignore it. Either way we have to clear the exception before continuing.
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa
>>>>>
>>>>> 2016/04/19 22:43 "Yasumasa Suenaga" <yasuenag at gmail.com
>>>>> <mailto:yasuenag at gmail.com>>:
>>>>>  >
>>>>>  > Hi David,
>>>>>  >
>>>>>  > Thank you for your comment.
>>>>>  > I uploaded new webrev. Could you review again?
>>>>>  >
>>>>>  >  - hotspot:
>>>>>  > http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.04/hotspot/
>>>>>  >
>>>>>  >  - jdk:
>>>>>  > http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.04/jdk/
>>>>>  >
>>>>>  >
>>>>>  >> That aside I'm not sure why you do this so late in the process, I
>>>>> would have done it immediately after here:
>>>>>  >
>>>>>  >
>>>>>  > I think that native thread name ("main") should be set just before
>>>>>  > main method call.
>>>>>  > However, main thread is already started, so I moved it as you suggested.
>>>>>  >
>>>>>  >
>>>>>  >> One thing I dislike about the current structure is that we have to
>>>>> go from char* to java.lang.String to call setNativeName which then calls
>>>>> JVM_SetNativeThreadName which converts the j.l.String back to a char* !
>>>>>  >
>>>>>  >
>>>>>  > SoI proposed to export new JVM function to set native thread name with
>>>>>  > const char *.
>>>>>  >
>>>>>  >
>>>>>  > Thanks,
>>>>>  >
>>>>>  > Yasumasa
>>>>>  >
>>>>>  >
>>>>>  >
>>>>>  > On 2016/04/19 14:04, David Holmes wrote:
>>>>>  >>
>>>>>  >> Hi Yasumasa,
>>>>>  >>
>>>>>  >> Thanks for persevering with this to get it into the current form.
>>>>> Sorry I haven't been able to do a detailed review until now.
>>>>>  >>
>>>>>  >> On 19/04/2016 9:28 AM, Yasumasa Suenaga wrote:
>>>>>  >>>
>>>>>  >>> Hi Gerard,
>>>>>  >>>
>>>>>  >>> 2016/04/19 3:14 "Gerard Ziemski" <gerard.ziemski at oracle.com
>>>>> <mailto:gerard.ziemski at oracle.com>
>>>>>  >>> <mailto:gerard.ziemski at oracle.com <mailto:gerard.ziemski at oracle.com>>>:
>>>>>  >>>  >
>>>>>  >>>  > hi Yasumasa,
>>>>>  >>>  >
>>>>>  >>>  > Nice work. I have 2 questions:
>>>>>  >>>  >
>>>>>  >>>  > ========
>>>>>  >>>  > File: java.c
>>>>>  >>>  >
>>>>>  >>>  > #1 Shouldn’t we be checking for “(*env)->ExceptionOccurred(env)”
>>>>>  >>> after every single JNI call? In this example instead of NULL_CHECK,
>>>>>  >>> should we be using CHECK_EXCEPTION_NULL_LEAVE macro?
>>>>>  >>>
>>>>>  >>> It is not critical if we encounter error at JNI function call because
>>>>>  >>> we cannot set native thread name only.
>>>>>  >>> So I think that we do not need to leave from launcher process.
>>>>>  >>
>>>>>  >>
>>>>>  >> I agree we do not need to abort if an exception occurs (and in fact
>>>>> I don't think an exception is even possible from this code), but we
>>>>> should ensure any pending exception is cleared before any futher JNI
>>>>> calls might be made. Note that NULL_CHECK is already used extensively
>>>>> throughout the launcher code - so if this usage is wrong then it is all
>>>>> wrong! More on this code below ...
>>>>>  >>
>>>>>  >> Other comments:
>>>>>  >>
>>>>>  >> hotspot/src/share/vm/prims/jvm.cpp
>>>>>  >>
>>>>>  >> Please add a comment to the method now that you removed the internal
>>>>> comment:
>>>>>  >>
>>>>>  >> // Sets the native thread name for a JavaThread. If specifically
>>>>>  >> // requested JNI-attached threads can also have their native name set;
>>>>>  >> // otherwise we do not modify JNI-attached threads as it may interfere
>>>>>  >> // with the application that created them.
>>>>>  >>
>>>>>  >> ---
>>>>>  >>
>>>>>  >> jdk/src/java.base/share/classes/java/lang/Thread.java
>>>>>  >>
>>>>>  >> Please add the following comments:
>>>>>  >>
>>>>>  >> +            // Don't modify JNI-attached threads
>>>>>  >>               setNativeName(name, false);
>>>>>  >>
>>>>>  >> + // May be called directly via JNI or reflection (when permitted) to
>>>>>  >> + // allow JNI-attached threads to set their native name
>>>>>  >>   private native void setNativeName(String name, boolean
>>>>> allowAttachedThread);
>>>>>  >>
>>>>>  >> ---
>>>>>  >>
>>>>>  >> jd/src/java.base/share/native/libjli/java.c
>>>>>  >>
>>>>>  >> 328 #define LEAVE() \
>>>>>  >> 329     SetNativeThreadName(env, "DestroyJavaVM"); \
>>>>>  >>
>>>>>  >> I was going to suggest this be set later, but realized we have to be
>>>>> attached to do this and that happens inside DestroyJavaVM. :)
>>>>>  >>
>>>>>  >> +     /* Set native thread name. */
>>>>>  >> +     SetNativeThreadName(env, "main");
>>>>>  >>
>>>>>  >> The comment is redundant given the name of the method. That aside
>>>>> I'm not sure why you do this so late in the process, I would have done
>>>>> it immediately after here:
>>>>>  >>
>>>>>  >>   386     if (!InitializeJVM(&vm, &env, &ifn)) {
>>>>>  >>   387         JLI_ReportErrorMessage(JVM_ERROR1);
>>>>>  >>   388         exit(1);
>>>>>  >>   389     }
>>>>>  >>   +       SetNativeThreadName(env, "main");
>>>>>  >>
>>>>>  >>
>>>>>  >> + /**
>>>>>  >> +  * Set native thread name as possible.
>>>>>  >> +  */
>>>>>  >>
>>>>>  >> Other than the as->if change I'm unclear where the "possible" bit
>>>>> comes into play - why would it not be possible?
>>>>>  >>
>>>>>  >> 1705     NULL_CHECK(cls = FindBootStrapClass(env, "java/lang/Thread"));
>>>>>  >> 1706     NULL_CHECK(currentThreadID = (*env)->GetStaticMethodID(env,
>>>>> cls,
>>>>>  >> 1707 "currentThread",
>>>>> "()Ljava/lang/Thread;"));
>>>>>  >> 1708     NULL_CHECK(currentThread =
>>>>> (*env)->CallStaticObjectMethod(env, cls,
>>>>>  >> 1709 currentThreadID));
>>>>>  >> 1710     NULL_CHECK(setNativeNameID = (*env)->GetMethodID(env, cls,
>>>>>  >> 1711 "setNativeName",
>>>>> "(Ljava/lang/String;Z)V"));
>>>>>  >> 1712     NULL_CHECK(nameString = (*env)->NewStringUTF(env, name));
>>>>>  >> 1713     (*env)->CallVoidMethod(env, currentThread, setNativeNameID,
>>>>>  >> 1714                            nameString, JNI_TRUE);
>>>>>  >>
>>>>>  >> As above NULL_CHECK is fine here, but we should check for and clear
>>>>> any pending exception after CallVoidMethod.
>>>>>  >>
>>>>>  >> One thing I dislike about the current structure is that we have to
>>>>> go from char* to java.lang.String to call setNativeName which then calls
>>>>> JVM_SetNativeThreadName which converts the j.l.String back to a char* !
>>>>> Overall I wonder about the affect on startup cost. But if there is an
>>>>> issue we can revisit this.
>>>>>  >>
>>>>>  >> Thanks,
>>>>>  >> David
>>>>>  >> -----
>>>>>  >>
>>>>>  >>
>>>>>  >>>  > #2 Should the comment for “SetNativeThreadName” be “Set native
>>>>> thread
>>>>>  >>> name if possible.” not "Set native thread name as possible.”?
>>>>>  >>>
>>>>>  >>> Sorry for my bad English :-)
>>>>>  >>>
>>>>>  >>> Thanks,
>>>>>  >>>
>>>>>  >>> Yasumasa
>>>>>  >>>
>>>>>  >>>  > cheers
>>>>>  >>>  >
>>>>>  >>>  > > On Apr 16, 2016, at 4:29 AM, Yasumasa Suenaga
>>>>> <yasuenag at gmail.com <mailto:yasuenag at gmail.com>
>>>>>  >>> <mailto:yasuenag at gmail.com <mailto:yasuenag at gmail.com>>> wrote:
>>>>>  >>>  > >
>>>>>  >>>  > > Hi David,
>>>>>  >>>  > >
>>>>>  >>>  > > I uploaded new webrev:
>>>>>  >>>  > >
>>>>>  >>>  > > - hotspot:
>>>>>  >>>  > >
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.03/hotspot/
>>>>>  >>>  > >
>>>>>  >>>  > > - jdk:
>>>>>  >>>  > > http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.03/jdk/
>>>>>  >>>  > >
>>>>>  >>>  > >
>>>>>  >>>  > >> it won't work unless you change the semantics of setName so I'm
>>>>>  >>> not sure what you were thinking here. To take advantage of an arg
>>>>> taking
>>>>>  >>> JVM_SetNativThreadName you would need to call it directly as no Java
>>>>>  >>> code will call it . ???
>>>>>  >>>  > >
>>>>>  >>>  > > I added a flag for setting native thread name to JNI-attached
>>>>> thread.
>>>>>  >>>  > > This change can set native thread name if main thread changes to
>>>>>  >>> JNI-attached thread.
>>>>>  >>>  > >
>>>>>  >>>  > >
>>>>>  >>>  > > Thanks,
>>>>>  >>>  > >
>>>>>  >>>  > > Yasumasa
>>>>>  >>>  > >
>>>>>  >>>  > >
>>>>>  >>>  > > On 2016/04/16 16:11, David Holmes wrote:
>>>>>  >>>  > >> On 16/04/2016 3:27 PM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>> Hi David,
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>> That change in behaviour may be a problem, it could be
>>>>> considered a
>>>>>  >>>  > >>>> regression that setName stops setting the native thread
>>>>> main, even
>>>>>  >>>  > >>>> though we never really intended it to work in the first place.
>>>>>  >>> :( Such
>>>>>  >>>  > >>>> a change needs to go through CCC.
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> I understood.
>>>>>  >>>  > >>> Can I send CCC request?
>>>>>  >>>  > >>> (I'm jdk 9 commiter, but I'm not employee at Oracle.)
>>>>>  >>>  > >>
>>>>>  >>>  > >> Sorry you can't file a CCC request, you would need a sponsor for
>>>>>  >>> that. But at this stage I don't think I agree with the proposed change
>>>>>  >>> because of the change in behaviour - there's no way to restore the
>>>>>  >>> "broken" behaviour.
>>>>>  >>>  > >>
>>>>>  >>>  > >>> I want to continue to discuss about it on JDK-8154331 [1].
>>>>>  >>>  > >>
>>>>>  >>>  > >> Okay we can do that.
>>>>>  >>>  > >>
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>> Further, we expect the launcher to use the supported JNI
>>>>>  >>> interface (as
>>>>>  >>>  > >>>> other processes would), not the internal JVM interface that
>>>>>  >>> exists for
>>>>>  >>>  > >>>> the JDK sources to communicate with the JVM.
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> I think that we do not use JVM interface if we add new method in
>>>>>  >>>  > >>> LauncherHelper as below:
>>>>>  >>>  > >>> ----------------
>>>>>  >>>  > >>> diff -r f02139a1ac84
>>>>>  >>>  > >>> src/java.base/share/classes/sun/launcher/LauncherHelper.java
>>>>>  >>>  > >>> ---
>>>>> a/src/java.base/share/classes/sun/launcher/LauncherHelper.java
>>>>>  >>>  > >>> Wed Apr 13 14:19:30 2016 +0000
>>>>>  >>>  > >>> +++
>>>>> b/src/java.base/share/classes/sun/launcher/LauncherHelper.java
>>>>>  >>>  > >>> Sat Apr 16 11:25:53 2016 +0900
>>>>>  >>>  > >>> @@ -960,4 +960,8 @@
>>>>>  >>>  > >>>          else
>>>>>  >>>  > >>>              return md.toNameAndVersion() + " (" + loc + ")";
>>>>>  >>>  > >>>      }
>>>>>  >>>  > >>> +
>>>>>  >>>  > >>> +    static void setNativeThreadName(String name) {
>>>>>  >>>  > >>> + Thread.currentThread().setName(name);
>>>>>  >>>  > >>> +    }
>>>>>  >>>  > >>
>>>>>  >>>  > >> You could also make that call via JNI directly, so not sure the
>>>>>  >>> helper adds much here. But it won't work unless you change the
>>>>> semantics
>>>>>  >>> of setName so I'm not sure what you were thinking here. To take
>>>>>  >>> advantage of an arg taking JVM_SetNativThreadName you would need to
>>>>> call
>>>>>  >>> it directly as no Java code will call it . ???
>>>>>  >>>  > >>
>>>>>  >>>  > >> David
>>>>>  >>>  > >> -----
>>>>>  >>>  > >>
>>>>>  >>>  > >>>  }
>>>>>  >>>  > >>> diff -r f02139a1ac84 src/java.base/share/native/libjli/java.c
>>>>>  >>>  > >>> --- a/src/java.base/share/native/libjli/java.c    Wed Apr 13
>>>>> 14:19:30
>>>>>  >>>  > >>> 2016 +0000
>>>>>  >>>  > >>> +++ b/src/java.base/share/native/libjli/java.c    Sat Apr 16
>>>>> 11:25:53
>>>>>  >>>  > >>> 2016 +0900
>>>>>  >>>  > >>> @@ -125,6 +125,7 @@
>>>>>  >>>  > >>>  static void PrintUsage(JNIEnv* env, jboolean doXUsage);
>>>>>  >>>  > >>>  static void ShowSettings(JNIEnv* env, char *optString);
>>>>>  >>>  > >>>  static void ListModules(JNIEnv* env, char *optString);
>>>>>  >>>  > >>> +static void SetNativeThreadName(JNIEnv* env, char *name);
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>  static void SetPaths(int argc, char **argv);
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> @@ -325,6 +326,7 @@
>>>>>  >>>  > >>>   * mainThread.isAlive() to work as expected.
>>>>>  >>>  > >>>   */
>>>>>  >>>  > >>>  #define LEAVE() \
>>>>>  >>>  > >>> + SetNativeThreadName(env, "DestroyJavaVM"); \
>>>>>  >>>  > >>>      do { \
>>>>>  >>>  > >>>          if ((*vm)->DetachCurrentThread(vm) != JNI_OK) { \
>>>>>  >>>  > >>> JLI_ReportErrorMessage(JVM_ERROR2); \
>>>>>  >>>  > >>> @@ -488,6 +490,9 @@
>>>>>  >>>  > >>>      mainArgs = CreateApplicationArgs(env, argv, argc);
>>>>>  >>>  > >>> CHECK_EXCEPTION_NULL_LEAVE(mainArgs);
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> +    /* Set native thread name. */
>>>>>  >>>  > >>> + SetNativeThreadName(env, "main");
>>>>>  >>>  > >>> +
>>>>>  >>>  > >>>      /* Invoke main method. */
>>>>>  >>>  > >>> (*env)->CallStaticVoidMethod(env, mainClass, mainID,
>>>>> mainArgs);
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> @@ -1686,6 +1691,22 @@
>>>>>  >>>  > >>>                                   joptString);
>>>>>  >>>  > >>>  }
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> +/**
>>>>>  >>>  > >>> + * Set native thread name as possible.
>>>>>  >>>  > >>> + */
>>>>>  >>>  > >>> +static void
>>>>>  >>>  > >>> +SetNativeThreadName(JNIEnv *env, char *name)
>>>>>  >>>  > >>> +{
>>>>>  >>>  > >>> +    jmethodID setNativeThreadNameID;
>>>>>  >>>  > >>> +    jstring nameString;
>>>>>  >>>  > >>> +    jclass cls = GetLauncherHelperClass(env);
>>>>>  >>>  > >>> +    NULL_CHECK(cls);
>>>>>  >>>  > >>> + NULL_CHECK(setNativeThreadNameID =
>>>>>  >>> (*env)->GetStaticMethodID(env, cls,
>>>>>  >>>  > >>> + "setNativeThreadName", "(Ljava/lang/String;)V"));
>>>>>  >>>  > >>> +    NULL_CHECK(nameString = (*env)->NewStringUTF(env, name));
>>>>>  >>>  > >>> + (*env)->CallStaticVoidMethod(env, cls,
>>>>> setNativeThreadNameID,
>>>>>  >>>  > >>> nameString);
>>>>>  >>>  > >>> +}
>>>>>  >>>  > >>> +
>>>>>  >>>  > >>>  /*
>>>>>  >>>  > >>>   * Prints default usage or the Xusage message, see
>>>>>  >>>  > >>> sun.launcher.LauncherHelper.java
>>>>>  >>>  > >>>   */
>>>>>  >>>  > >>> ----------------
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> So I want to add new arg to JVM_SetNativeThreadName().
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>> However this is still a change to the exported JVM
>>>>> interface and so
>>>>>  >>>  > >>>> has to be approved.
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> Do you mean that this change needs CCC?
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> Thanks,
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> Yasumasa
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> [1]
>>>>>  >>>  > >>>
>>>>>  >>>
>>>>> http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2016-April/019034.html
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>
>>>>>  >>>  > >>>
>>>>>  >>>  > >>> On 2016/04/16 7:26, David Holmes wrote:
>>>>>  >>>  > >>>> On 15/04/2016 11:20 PM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>> Hi David,
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>>> I think it is a bug based on the comment here:
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> JavaThread(bool is_attaching_via_jni = false); // for main
>>>>>  >>> thread and
>>>>>  >>>  > >>>>>> JNI attached threads
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> I filed it to JBS as JDK-8154331.
>>>>>  >>>  > >>>>> I will send review request to hotspot-runtime-dev.
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>>> Though that will introduce a change in behaviour by itself as
>>>>>  >>> setName
>>>>>  >>>  > >>>>>> will no longer set the native name for the main thread.
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> I know.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>> That change in behaviour may be a problem, it could be
>>>>> considered a
>>>>>  >>>  > >>>> regression that setName stops setting the native thread
>>>>> main, even
>>>>>  >>>  > >>>> though we never really intended it to work in the first place.
>>>>>  >>> :( Such
>>>>>  >>>  > >>>> a change needs to go through CCC.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>>> I checked changeset history.
>>>>>  >>>  > >>>>> JVM_SetNativeThreadName() was introduced in JDK-7098194,
>>>>> and it is
>>>>>  >>>  > >>>>> backported JDK 8.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>> Yes this all came in as part of the OSX port in 7u2.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>>> However, this function seems to be called from
>>>>>  >>> Thread#setNativeName()
>>>>>  >>>  > >>>>> only.
>>>>>  >>>  > >>>>> In addition, Thread#setNativeName() is private method.
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> Thus I think that we can add an argument to
>>>>>  >>> JVM_SetNativeThreadName()
>>>>>  >>>  > >>>>> for force setting.
>>>>>  >>>  > >>>>> (e.g. "bool forced")
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> It makes a change of JVM API.
>>>>>  >>>  > >>>>> However, this function is NOT public, so I think we can
>>>>> add one
>>>>>  >>> more
>>>>>  >>>  > >>>>> argument.
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> What do you think about this?
>>>>>  >>>  > >>>>> If it is accepted, we can set native thread name from Java
>>>>>  >>> launcher.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>> The private/public aspect of the Java API is not really at
>>>>>  >>> issue. Yes
>>>>>  >>>  > >>>> we would add another arg to the JVM function to allow it to
>>>>> apply to
>>>>>  >>>  > >>>> JNI-attached threads as well (I'd prefer the arg reflect that
>>>>>  >>> not just
>>>>>  >>>  > >>>> "force"). However this is still a change to the exported JVM
>>>>>  >>> interface
>>>>>  >>>  > >>>> and so has to be approved. Further, we expect the launcher to
>>>>>  >>> use the
>>>>>  >>>  > >>>> supported JNI interface (as other processes would), not the
>>>>> internal
>>>>>  >>>  > >>>> JVM interface that exists for the JDK sources to communicate
>>>>>  >>> with the
>>>>>  >>>  > >>>> JVM.
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>> David
>>>>>  >>>  > >>>> -----
>>>>>  >>>  > >>>>
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> Thanks,
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> Yasumasa
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>>
>>>>>  >>>  > >>>>> On 2016/04/15 19:16, David Holmes wrote:
>>>>>  >>>  > >>>>>> Hi Yasumasa,
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> On 15/04/2016 6:53 PM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>> Hi David,
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>> The fact that the "main" thread is not tagged as being a
>>>>>  >>> JNI-attached
>>>>>  >>>  > >>>>>>>> thread seems accidental to me
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> Should I file it to JBS?
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> I think it is a bug based on the comment here:
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> JavaThread(bool is_attaching_via_jni = false); // for main
>>>>>  >>> thread and
>>>>>  >>>  > >>>>>> JNI attached threads
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> Though that will introduce a change in behaviour by itself as
>>>>>  >>> setName
>>>>>  >>>  > >>>>>> will no longer set the native name for the main thread.
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>>> I think that we can fix as below:
>>>>>  >>>  > >>>>>>> ---------------
>>>>>  >>>  > >>>>>>> diff -r 52aa0ee93b32 src/share/vm/runtime/thread.cpp
>>>>>  >>>  > >>>>>>> --- a/src/share/vm/runtime/thread.cpp   Thu Apr 14 13:31:11
>>>>>  >>> 2016 +0200
>>>>>  >>>  > >>>>>>> +++ b/src/share/vm/runtime/thread.cpp   Fri Apr 15 17:50:10
>>>>>  >>> 2016 +0900
>>>>>  >>>  > >>>>>>> @@ -3592,7 +3592,7 @@
>>>>>  >>>  > >>>>>>>  #endif // INCLUDE_JVMCI
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>    // Attach the main thread to this os thread
>>>>>  >>>  > >>>>>>> - JavaThread* main_thread = new JavaThread();
>>>>>  >>>  > >>>>>>> + JavaThread* main_thread = new JavaThread(true);
>>>>>  >>>  > >>>>>>> main_thread->set_thread_state(_thread_in_vm);
>>>>>  >>>  > >>>>>>> main_thread->initialize_thread_current();
>>>>>  >>>  > >>>>>>>    // must do this before set_active_handles
>>>>>  >>>  > >>>>>>> @@ -3776,6 +3776,9 @@
>>>>>  >>>  > >>>>>>>    // Notify JVMTI agents that VM initialization is complete
>>>>>  >>> - nop if
>>>>>  >>>  > >>>>>>> no agents.
>>>>>  >>>  > >>>>>>> JvmtiExport::post_vm_initialized();
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> +  // Change attach status to "attached"
>>>>>  >>>  > >>>>>>> + main_thread->set_done_attaching_via_jni();
>>>>>  >>>  > >>>>>>> +
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> I think we can do this straight after the JavaThread
>>>>> constructor.
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>>>    if (TRACE_START() != JNI_OK) {
>>>>>  >>>  > >>>>>>> vm_exit_during_initialization("Failed to start tracing
>>>>>  >>>  > >>>>>>> backend.");
>>>>>  >>>  > >>>>>>>    }
>>>>>  >>>  > >>>>>>> ---------------
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>> If it wants to name its native threads then it is free
>>>>> to do so,
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> Currently, JVM_SetNativeThreadName() cannot change native
>>>>>  >>> thread name
>>>>>  >>>  > >>>>>>> when the caller thread is JNI-attached thread.
>>>>>  >>>  > >>>>>>> However, I think that it should be changed if Java developer
>>>>>  >>> calls
>>>>>  >>>  > >>>>>>> Thread#setName() explicitly.
>>>>>  >>>  > >>>>>>> It is not the same of changing native thread name at
>>>>>  >>>  > >>>>>>> Threads::create_vm().
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> If it is allowed, I want to fix SetNativeThreadName() as
>>>>> below.
>>>>>  >>>  > >>>>>>> What do you think about this?
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> The decision to not change the name of JNI-attached
>>>>> threads was a
>>>>>  >>>  > >>>>>> deliberate one** - this functionality originated with the OSX
>>>>>  >>> port and
>>>>>  >>>  > >>>>>> it was reported that the initial feedback with this
>>>>> feature was to
>>>>>  >>>  > >>>>>> ensure it didn't mess with thread names that had been set by
>>>>>  >>> the host
>>>>>  >>>  > >>>>>> process. If we do as you propose then we will just have an
>>>>>  >>>  > >>>>>> inconsistency for people to complain about: "why does my
>>>>>  >>> native thread
>>>>>  >>>  > >>>>>> only have a name if I call cur.setName(cur.getName()) ?"
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> ** If you follow the bugs and related discussions on
>>>>> this, the
>>>>>  >>>  > >>>>>> semantics and limitations (truncation, current thread only,
>>>>>  >>> non-JNI
>>>>>  >>>  > >>>>>> threads only) of setting the native thread name were supposed
>>>>>  >>> to be
>>>>>  >>>  > >>>>>> documented in the release notes - but as far as I can see
>>>>> that
>>>>>  >>> never
>>>>>  >>>  > >>>>>> happened. :(
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> My position on this remains that if it is desirable for
>>>>> the main
>>>>>  >>>  > >>>>>> thread (and DestroyJavaVM thread) to have native names
>>>>> then the
>>>>>  >>>  > >>>>>> launcher needs to be setting them using the available
>>>>> platform
>>>>>  >>> APIs.
>>>>>  >>>  > >>>>>> Unfortunately this is complicated - as evidenced by the VM
>>>>>  >>> code for
>>>>>  >>>  > >>>>>> this - due to the need to verify API availability.
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> Any change in behaviour in relation to Thread.setName would
>>>>>  >>> have to go
>>>>>  >>>  > >>>>>> through our CCC process I think. But a change in the launcher
>>>>>  >>> would
>>>>>  >>>  > >>>>>> not.
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> Sorry.
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>> David
>>>>>  >>>  > >>>>>> -----
>>>>>  >>>  > >>>>>>
>>>>>  >>>  > >>>>>>> ---------------
>>>>>  >>>  > >>>>>>> --- a/src/share/vm/prims/jvm.cpp        Thu Apr 14 13:31:11
>>>>>  >>> 2016 +0200
>>>>>  >>>  > >>>>>>> +++ b/src/share/vm/prims/jvm.cpp        Fri Apr 15 17:50:10
>>>>>  >>> 2016 +0900
>>>>>  >>>  > >>>>>>> @@ -3187,7 +3187,7 @@
>>>>>  >>>  > >>>>>>> JavaThread* thr = java_lang_Thread::thread(java_thread);
>>>>>  >>>  > >>>>>>>    // Thread naming only supported for the current thread,
>>>>>  >>> doesn't
>>>>>  >>>  > >>>>>>> work
>>>>>  >>>  > >>>>>>> for
>>>>>  >>>  > >>>>>>>    // target threads.
>>>>>  >>>  > >>>>>>> -  if (Thread::current() == thr &&
>>>>>  >>> !thr->has_attached_via_jni()) {
>>>>>  >>>  > >>>>>>> +  if (Thread::current() == thr) {
>>>>>  >>>  > >>>>>>>      // we don't set the name of an attached thread to avoid
>>>>>  >>> stepping
>>>>>  >>>  > >>>>>>>      // on other programs
>>>>>  >>>  > >>>>>>>      const char *thread_name =
>>>>>  >>>  > >>>>>>>
>>>>>  >>> java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
>>>>>  >>>  > >>>>>>> ---------------
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>>
>>>>>  >>>  > >>>>>>> On 2016/04/15 13:32, David Holmes wrote:
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>> On 15/04/2016 1:11 AM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>> Roger,
>>>>>  >>>  > >>>>>>>>> Thanks for your comment!
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>> David,
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> I'll wait to see what Kumar thinks about this. I
>>>>> don't like
>>>>>  >>>  > >>>>>>>>>>>> exposing
>>>>>  >>>  > >>>>>>>>>>>> a new JVM function this way.
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>> I tried to call Thread#setName() after initializing VM
>>>>> (before
>>>>>  >>>  > >>>>>>>>> calling
>>>>>  >>>  > >>>>>>>>> main method),
>>>>>  >>>  > >>>>>>>>> I could set native thread name.
>>>>>  >>>  > >>>>>>>>> However, DestroyJavaVM() calls AttachCurrentThread().
>>>>> So we
>>>>>  >>> can't
>>>>>  >>>  > >>>>>>>>> set
>>>>>  >>>  > >>>>>>>>> native thread name for DestroyJavaVM.
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>> Right - I came to the same realization earlier this
>>>>> morning.
>>>>>  >>> Which,
>>>>>  >>>  > >>>>>>>> unfortunately, takes me back to the basic premise here that
>>>>>  >>> we don't
>>>>>  >>>  > >>>>>>>> set the name of threads not created by the JVM. The fact
>>>>>  >>> that the
>>>>>  >>>  > >>>>>>>> "main" thread is not tagged as being a JNI-attached
>>>>> thread seems
>>>>>  >>>  > >>>>>>>> accidental to me - so JVM_SetNativeThreadName is only
>>>>> working by
>>>>>  >>>  > >>>>>>>> accident for the initial attach, and can't be used for the
>>>>>  >>>  > >>>>>>>> DestroyJavaVM part - which leaves the thread inconsistently
>>>>>  >>> named at
>>>>>  >>>  > >>>>>>>> the native level.
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>> I'm afraid my view here is that the launcher has to be
>>>>>  >>> treated like
>>>>>  >>>  > >>>>>>>> any other process that might host a JVM. If it wants to
>>>>> name its
>>>>>  >>>  > >>>>>>>> native threads then it is free to do so, but I would not be
>>>>>  >>> exporting
>>>>>  >>>  > >>>>>>>> a function from the JVM to do that - it would have to
>>>>> use the OS
>>>>>  >>>  > >>>>>>>> specific API's for that on a platform-by-platform basis.
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>> Sorry.
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>> David
>>>>>  >>>  > >>>>>>>> -----
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>>
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>>
>>>>>  >>>  > >>>>>>>>> On 2016/04/14 23:24, Roger Riggs wrote:
>>>>>  >>>  > >>>>>>>>>> Hi,
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> Comments:
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> jvm.h:  The function names are too similar but perform
>>>>>  >>> different
>>>>>  >>>  > >>>>>>>>>> functions:
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> -JVM_SetNativeThreadName0 vs JVM_SetNativeThreadName
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> -  The first function applies to the current thread, the
>>>>>  >>> second
>>>>>  >>>  > >>>>>>>>>> one a
>>>>>  >>>  > >>>>>>>>>> specific java thread.
>>>>>  >>>  > >>>>>>>>>> It would seem useful for there to be a comment somewhere
>>>>>  >>> about
>>>>>  >>>  > >>>>>>>>>> what
>>>>>  >>>  > >>>>>>>>>> the new function does.
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> windows/native/libjli/java_md.c: line 408 casts to
>>>>> (void*)
>>>>>  >>>  > >>>>>>>>>> instead of
>>>>>  >>>  > >>>>>>>>>> (SetNativeThreadName0_t)
>>>>>  >>>  > >>>>>>>>>>    as is done on unix and mac.
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> - macosx/native/libjli/java_md_macosx.c:
>>>>>  >>>  > >>>>>>>>>> - 737: looks wrong to overwriteifn->GetCreatedJavaVMs
>>>>>  >>> used at
>>>>>  >>>  > >>>>>>>>>> line 730
>>>>>  >>>  > >>>>>>>>>> - 738  Incorrect indentation; if possible keep the cast
>>>>>  >>> on the
>>>>>  >>>  > >>>>>>>>>> same
>>>>>  >>>  > >>>>>>>>>> line as dlsym...
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> $.02, Roger
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>> On 4/14/2016 9:32 AM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>> That is an interesting question which I haven't had
>>>>> time to
>>>>>  >>>  > >>>>>>>>>>>> check -
>>>>>  >>>  > >>>>>>>>>>>> sorry. If the main thread is considered a JNI-attached
>>>>>  >>> thread
>>>>>  >>>  > >>>>>>>>>>>> then
>>>>>  >>>  > >>>>>>>>>>>> my suggestion wont work. If it isn't then my suggestion
>>>>>  >>> should
>>>>>  >>>  > >>>>>>>>>>>> work
>>>>>  >>>  > >>>>>>>>>>>> (but it means we have an inconsistency in our
>>>>> treatment of
>>>>>  >>>  > >>>>>>>>>>>> JNI-attached threads :( )
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>> I ran following program on JDK 9 EA b112, and I
>>>>> confirmed
>>>>>  >>> native
>>>>>  >>>  > >>>>>>>>>>> thread name (test) was set.
>>>>>  >>>  > >>>>>>>>>>> ---------
>>>>>  >>>  > >>>>>>>>>>> public class Sleep{
>>>>>  >>>  > >>>>>>>>>>>  public static void main(String[] args) throws
>>>>> Exception{
>>>>>  >>>  > >>>>>>>>>>> Thread.currentThread().setName("test");
>>>>>  >>>  > >>>>>>>>>>> Thread.sleep(3600000);
>>>>>  >>>  > >>>>>>>>>>>  }
>>>>>  >>>  > >>>>>>>>>>> }
>>>>>  >>>  > >>>>>>>>>>> ---------
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> I'll wait to see what Kumar thinks about this. I
>>>>> don't like
>>>>>  >>>  > >>>>>>>>>>>> exposing
>>>>>  >>>  > >>>>>>>>>>>> a new JVM function this way.
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>> I will update webrev after hearing Kumar's comment.
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>> On 2016/04/14 21:32, David Holmes wrote:
>>>>>  >>>  > >>>>>>>>>>>> On 14/04/2016 1:52 PM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>> Hi,
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> On 2016/04/14 9:34, David Holmes wrote:
>>>>>  >>>  > >>>>>>>>>>>>>> Hi,
>>>>>  >>>  > >>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>> On 14/04/2016 1:28 AM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>> Hi David,
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> Thanks for your comment.
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> I exported new JVM function to set native thread
>>>>>  >>> name, and JLI
>>>>>  >>>  > >>>>>>>>>>>>>>> uses it
>>>>>  >>>  > >>>>>>>>>>>>>>> in new webrev.
>>>>>  >>>  > >>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>> First the launcher belongs to another team so
>>>>>  >>> core-libs will
>>>>>  >>>  > >>>>>>>>>>>>>> need to
>>>>>  >>>  > >>>>>>>>>>>>>> review and approve this (in particular Kumar) -
>>>>> now cc'd.
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> Thanks!
>>>>>  >>>  > >>>>>>>>>>>>> I'm waiting to review :-)
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>> Personally I would have used a Java upcall to
>>>>>  >>> Thread.setName
>>>>>  >>>  > >>>>>>>>>>>>>> rather
>>>>>  >>>  > >>>>>>>>>>>>>> than exporting JVM_SetNativeThreadName. No
>>>>> hotspot changes
>>>>>  >>>  > >>>>>>>>>>>>>> needed in
>>>>>  >>>  > >>>>>>>>>>>>>> that case.
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> As I wrote [1] in JBS, I changed to use
>>>>> Thread#setName() in
>>>>>  >>>  > >>>>>>>>>>>>> Thread#init(),
>>>>>  >>>  > >>>>>>>>>>>>> but I could not change native thread name.
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> At Thread.init time the thread is not alive, which is
>>>>>  >>> why the
>>>>>  >>>  > >>>>>>>>>>>> native
>>>>>  >>>  > >>>>>>>>>>>> name is not set.
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> I guess that caller of main() is JNI attached thread.
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> That is an interesting question which I haven't had
>>>>> time to
>>>>>  >>>  > >>>>>>>>>>>> check -
>>>>>  >>>  > >>>>>>>>>>>> sorry. If the main thread is considered a JNI-attached
>>>>>  >>> thread
>>>>>  >>>  > >>>>>>>>>>>> then
>>>>>  >>>  > >>>>>>>>>>>> my suggestion wont work. If it isn't then my suggestion
>>>>>  >>> should
>>>>>  >>>  > >>>>>>>>>>>> work
>>>>>  >>>  > >>>>>>>>>>>> (but it means we have an inconsistency in our
>>>>> treatment of
>>>>>  >>>  > >>>>>>>>>>>> JNI-attached threads :( )
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> I'll wait to see what Kumar thinks about this. I
>>>>> don't like
>>>>>  >>>  > >>>>>>>>>>>> exposing
>>>>>  >>>  > >>>>>>>>>>>> a new JVM function this way.
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>> David
>>>>>  >>>  > >>>>>>>>>>>> -----
>>>>>  >>>  > >>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> Thus I think that we have to provide a function to set
>>>>>  >>> native
>>>>>  >>>  > >>>>>>>>>>>>> thread name.
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>> [1]
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>
>>>>> https://bugs.openjdk.java.net/browse/JDK-8152690?focusedCommentId=13926851&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13926851
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>> David
>>>>>  >>>  > >>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> Could you review again?
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> - hotspot:
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.02/hotspot/
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> - jdk:
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.02/jdk/
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>> On 2016/04/13 22:00, David Holmes wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>> I'll answer on this original thread as well ...
>>>>>  >>>  > >>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>> Hi Yasumasa,
>>>>>  >>>  > >>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>> Please see my updates to the bug (sorry have
>>>>> been on
>>>>>  >>>  > >>>>>>>>>>>>>>>> vacation).
>>>>>  >>>  > >>>>>>>>>>>>>>>> This
>>>>>  >>>  > >>>>>>>>>>>>>>>> needs to be done in the launcher to be correct
>>>>> as we
>>>>>  >>> do not
>>>>>  >>>  > >>>>>>>>>>>>>>>> set the
>>>>>  >>>  > >>>>>>>>>>>>>>>> name of threads that attach via JNI, which
>>>>> includes the
>>>>>  >>>  > >>>>>>>>>>>>>>>> "main"
>>>>>  >>>  > >>>>>>>>>>>>>>>> thread.
>>>>>  >>>  > >>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>> David
>>>>>  >>>  > >>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>> On 31/03/2016 9:49 AM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>> Thanks Robbin,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>> I'm waiting a sponsor and more reviewer :-)
>>>>>  >>>  > >>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>>> 2016/03/31 5:58 "Robbin Ehn"
>>>>> <robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>>:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>> FYI: I'm not a Reviewer.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>> /Robbin
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>> On 03/30/2016 10:55 PM, Robbin Ehn wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>> Thanks, looks good.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>> /Robbin
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>> On 03/30/2016 03:47 PM, Yasumasa Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> Hi,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> I uploaded new webrev.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> Could you review it?
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.01/
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>> On 2016/03/30 19:10, Robbin Ehn wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> Hi,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> On 03/30/2016 11:41 AM, Yasumasa Suenaga
>>>>> wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Hi Robbin,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 2016/03/30 18:22 "Robbin Ehn"
>>>>>  >>> <robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>
>>>>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> <mailto:robbin.ehn at oracle.com
>>>>> <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>>>:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > Hi Yasumasa,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > On 03/25/2016 12:48 AM, Yasumasa
>>>>> Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> Hi Robbin,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> 2016/03/25 1:51 "Robbin Ehn"
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> <robbin.ehn at oracle.com
>>>>> <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> <mailto:robbin.ehn at oracle.com
>>>>> <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> <mailto:robbin.ehn at oracle.com
>>>>> <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> <mailto:robbin.ehn at oracle.com
>>>>> <mailto:robbin.ehn at oracle.com>
>>>>>  >>> <mailto:robbin.ehn at oracle.com <mailto:robbin.ehn at oracle.com>>>>>:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > Hi Yasumasa,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > I'm not sure why you don't set it:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > diff -r ded6ef79c770
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> src/share/vm/runtime/thread.cpp
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > ---
>>>>> a/src/share/vm/runtime/thread.cpp   Thu
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Mar 24
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 13:09:16 2016
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> +0000
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > +++
>>>>> b/src/share/vm/runtime/thread.cpp   Thu
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Mar 24
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 17:40:09 2016
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> +0100
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > @@ -3584,6 +3584,7 @@
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >    JavaThread* main_thread = new
>>>>>  >>> JavaThread();
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>> main_thread->set_thread_state(_thread_in_vm);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>> main_thread->initialize_thread_current();
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > +
>>>>>  >>> main_thread->set_native_thread_name("main");
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >    // must do this before
>>>>>  >>> set_active_handles
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>> main_thread->record_stack_base_and_size();
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>> main_thread->set_active_handles(JNIHandleBlock::allocate_block());
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > here instead? Am I missing something?
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> Native thread name is the same to thread
>>>>>  >>> name in
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Thread
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> class.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> It is set in c'tor in Thread or
>>>>> setName().
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> If you create new thread in Java app,
>>>>> native
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> name
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> will be
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> set at
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> startup. However, main thread is already
>>>>>  >>> starte
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> in VM.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> Thread name for "main" is set in
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> create_initial_thread().
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> I think that the place of setting
>>>>> thrrad name
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> should
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> be the
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> same.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > Yes, I see your point. But then
>>>>> something like
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> this is
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> nicer, no?
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > --- a/src/share/vm/runtime/thread.cpp
>>>>>   Tue
>>>>>  >>> Mar 29
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 09:43:05
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 2016
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> +0200
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +++ b/src/share/vm/runtime/thread.cpp
>>>>>   Wed
>>>>>  >>> Mar 30
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 10:51:12
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 2016
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> +0200
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > @@ -981,6 +981,7 @@
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >  // Creates the initial Thread
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >  static oop create_initial_thread(Handle
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread_group,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> JavaThread*
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > TRAPS) {
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +  static const char*
>>>>> initial_thread_name =
>>>>>  >>> "main";
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >    Klass* k =
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>> SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(),
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> true,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> CHECK_NULL);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >    instanceKlassHandle klass (THREAD, k);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >    instanceHandle thread_oop =
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> klass->allocate_instance_handle(CHECK_NULL);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > @@ -988,8 +989,10 @@
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > java_lang_Thread::set_thread(thread_oop(),
>>>>>  >>> thread);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>> java_lang_Thread::set_priority(thread_oop(),
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> NormPriority);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > thread->set_threadObj(thread_oop());
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > -
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > -  Handle string =
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> java_lang_String::create_from_str("main",
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> CHECK_NULL);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>> thread->set_native_thread_name(initial_thread_name);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > +  Handle string =
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>> java_lang_String::create_from_str(initial_thread_name,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> CHECK_NULL);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >    JavaValue result(T_VOID);
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > JavaCalls::call_special(&result,
>>>>> thread_oop,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Okay, I will upload new webrev later.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> Thanks!
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > The launcher seem to name itself
>>>>> 'java' and
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> naming
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> this
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> just
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > 'main' is confusing to me.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > E.g. so main thread of the process
>>>>> (and
>>>>>  >>> thus
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> the
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> process) is
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> 'java' but
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > first JavaThread is 'main'.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> The native main thread in the process
>>>>> is not
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> JavaThread.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> It is
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> waiting
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> for ending of Java main thread with
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> pthread_join().
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> set_native_thread_name() is for
>>>>>  >>> JavaThread. So I
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> think that
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> we do
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> not
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> need to call it for native main thread.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > Not sure if we can change it anyhow, since
>>>>>  >>> we want
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> java and
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> native
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> name to be the same and java thread name
>>>>> might
>>>>>  >>> have
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> some
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> dependents.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > The name is visible in e.g. /proc.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > $ ps H -C java -o 'pid tid comm' | head -4
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >   PID   TID COMMAND
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >  6423  6423 java
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >  6423  6424 main
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >  6423  6425 GC Thread#0
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > It would be nice with something like
>>>>> 'Java Main
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Thread'.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> I do not think so.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Native main thread might not be a Java
>>>>>  >>> launcher - e.g.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Apache
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> commons-daemon, JNI application, etc.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> If you want to change native main thread
>>>>> name,
>>>>>  >>> I think
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> that we
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> have to
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> change Java launcher code.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Should I include it in new webrev?
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> No
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> Thanks again!
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>> /Robbin
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > Thanks
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> > /Robbin
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >> Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > Thanks!
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > /Robbin
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > On 03/24/2016 03:26 PM, Yasumasa
>>>>>  >>> Suenaga wrote:
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > Hi all,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > HotSpot for Linux will set thread
>>>>>  >>> name via
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> pthread_setname_np().
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > However, main thread does not
>>>>> have it.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > All JavaThread have native name,
>>>>> and main
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread is
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> JavaThread.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > For consistency, main thread
>>>>> should have
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> native
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> thread
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> name.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > I uploaded a webrev. Could you
>>>>> review it?
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>> http://cr.openjdk.java.net/~ysuenaga/JDK-8152690/webrev.00/
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > I cannot access JPRT.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > So I need a sponsor.
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > Thanks,
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > > Yasumasa
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>  > >
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>> >>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>>>>>>>>>>>>>
>>>>>  >>>  > >>>>>>>>>>
>>>>>  >>>  >
>>>>>  >>>
>>>>>
>>
>



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