RFR: JDK-8152690: main thread does not have native thread name
David Holmes
david.holmes at oracle.com
Fri Apr 22 06:33:44 UTC 2016
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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