RFR: JDK-8152690: main thread does not have native thread name
Yasumasa Suenaga
yasuenag at gmail.com
Mon Apr 18 23:28:32 UTC 2016
Hi Gerard,
2016/04/19 3:14 "Gerard Ziemski" <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.
> #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>
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>:
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> 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>>:
> >>>>>>>>>>>>>>>>>>>>>> >
> >>>>>>>>>>>>>>>>>>>>>> > 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>>>:
> >>>>>>>>>>>>>>>>>>>>>> >>
> >>>>>>>>>>>>>>>>>>>>>> >> >
> >>>>>>>>>>>>>>>>>>>>>> >> > 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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