% hg backout

is the usual way to do this...

Dan


On 9/18/19 8:17 PM, Hohensee, Paul wrote:
Is there a tool that will generate a reversal patch?

On 9/18/19, 5:14 PM, "Daniel D. Daugherty" <daniel.daughe...@oracle.com> wrote:

      > Shall I go with that, or reverse the original patch?
I'm a bit worried about what else might show up since the
     NSK monitoring tests were not run prior to this push.
I vote for backing out the fix until proper testing has
     been done (and at least the one problem fixed...)
Dan On 9/18/19 8:00 PM, Hohensee, Paul wrote:
     > They all implement com.sun.management.ThreadMXBean, so adding a 
getCurrentThreadAllocatedBytes broke them. Potential fix is to give it a default 
implementation, vis
     >
     >      public default long getCurrentThreadAllocatedBytes() {
     >          return -1;
     >      }
     >
     > Shall I go with that, or reverse the original patch?
     >
     > On 9/18/19, 4:48 PM, "serviceability-dev on behalf of Hohensee, Paul" 
<serviceability-dev-boun...@openjdk.java.net on behalf of hohen...@amazon.com> wrote:
     >
     >      I'll take a look.
     >
     >      On 9/18/19, 4:40 PM, "David Holmes" <david.hol...@oracle.com> wrote:
     >
     >          Paul,
     >
     >          Unfortunately this patch has broken the 
vmTestbase/nsk/monitoring tests:
     >
     >          [2019-09-18T22:59:32,349Z]
     >          
/scratch/mesos/jib-master/install/jdk-14+15-615/src.full/open/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/server/ServerThreadMXBeanNew.java:32:
     >          error: ServerThreadMXBeanNew is not abstract and does not 
override
     >          abstract method getCurrentThreadAllocatedBytes() in ThreadMXBean
     >
     >          and possibly other issues as we are seeing hundreds of failures.
     >
     >          David
     >
     >          On 18/09/2019 8:50 am, David Holmes wrote:
     >          > On 18/09/2019 12:10 am, Hohensee, Paul wrote:
     >          >> Thanks, Serguei. :)
     >          >>
     >          >> David, are you ok with the patch?
     >          >
     >          > Yep, nothing further from me.
     >          >
     >          > David
     >          >
     >          >> Paul
     >          >>
     >          >> *From: *"serguei.spit...@oracle.com" 
<serguei.spit...@oracle.com>
     >          >> *Date: *Tuesday, September 17, 2019 at 2:26 AM
     >          >> *To: *"Hohensee, Paul" <hohen...@amazon.com>, David Holmes
     >          >> <david.hol...@oracle.com>, Mandy Chung 
<mandy.ch...@oracle.com>
     >          >> *Cc: *OpenJDK Serviceability 
<serviceability-dev@openjdk.java.net>,
     >          >> "hotspot-gc-...@openjdk.java.net" 
<hotspot-gc-...@openjdk.java.net>
     >          >> *Subject: *Re: RFR (M): 8207266:
     >          >> ThreadMXBean::getThreadAllocatedBytes() can be quicker for 
self thread
     >          >>
     >          >> Hi Paul,
     >          >>
     >          >> Thank you for refactoring and fixing the test.
     >          >> It looks great now!
     >          >>
     >          >> Thanks,
     >          >> Serguei
     >          >>
     >          >>
     >          >> On 9/15/19 02:52, Hohensee, Paul wrote:
     >          >>
     >          >>     Hi, Serguei, thanks for the review. New webrev at
     >          >>
     >          >>     http://cr.openjdk.java.net/~phh/8207266/webrev.09/
     >          >>
     >          >>     I refactored the test’s main() method, and you’re 
correct,
     >          >>     getThreadAllocatedBytes should be 
getCurrentThreadAllocatedBytes in
     >          >>     that context: fixed.
     >          >>
     >          >>     Paul
     >          >>
     >          >>     *From: *"serguei.spit...@oracle.com"
     >          >>     <mailto:serguei.spit...@oracle.com> 
<serguei.spit...@oracle.com>
     >          >>     <mailto:serguei.spit...@oracle.com>
     >          >>     *Organization: *Oracle Corporation
     >          >>     *Date: *Friday, September 13, 2019 at 5:50 PM
     >          >>     *To: *"Hohensee, Paul" <hohen...@amazon.com>
     >          >>     <mailto:hohen...@amazon.com>, David Holmes 
<david.hol...@oracle.com>
     >          >>     <mailto:david.hol...@oracle.com>, Mandy Chung
     >          >>     <mandy.ch...@oracle.com> <mailto:mandy.ch...@oracle.com>
     >          >>     *Cc: *OpenJDK Serviceability 
<serviceability-dev@openjdk.java.net>
     >          >>     <mailto:serviceability-dev@openjdk.java.net>,
     >          >>     "hotspot-gc-...@openjdk.java.net"
     >          >>     <mailto:hotspot-gc-...@openjdk.java.net>
     >          >>     <hotspot-gc-...@openjdk.java.net>
     >          >>     <mailto:hotspot-gc-...@openjdk.java.net>
     >          >>     *Subject: *Re: RFR (M): 8207266:
     >          >>     ThreadMXBean::getThreadAllocatedBytes() can be quicker 
for self
     >          >> thread
     >          >>
     >          >>     Hi Paul,
     >          >>
     >          >>     It looks pretty good in general.
     >          >>
     >          >>
     >          >> 
http://cr.openjdk.java.net/~phh/8207266/webrev.08/test/jdk/com/sun/management/ThreadMXBean/ThreadAllocatedMemory.java.frames.html
     >          >>
     >          >>
     >          >>     It would be nice to refactor the java main() method as 
it becomes
     >          >>     too big.
     >          >>     Two ways ofgetCurrentThreadAllocatedBytes() testing are 
good
     >          >> candidates
     >          >>     to become separate methods.
     >          >>
     >          >>        98         long size1 = 
mbean.getThreadAllocatedBytes(id);
     >          >>
     >          >>     Just wanted to double check if you wanted to invoke
     >          >>     the getCurrentThreadAllocatedBytes() instead as it is
     >          >>     a part of:
     >          >>
     >          >>        85         // First way, 
getCurrentThreadAllocatedBytes
     >          >>
     >          >>
     >          >>     Thanks,
     >          >>     Serguei
     >          >>
     >          >>     On 9/13/19 12:11 PM, Hohensee, Paul wrote:
     >          >>
     >          >>         Hi David, thanks for your comments. New webrev in
     >          >>
     >          >>
     >          >>         http://cr.openjdk.java.net/~phh/8207266/webrev.08/
     >          >>
     >          >>
     >          >>         Both the old and new versions of the code check that 
thread
     >          >> allocated memory is both supported and enabled. The existing 
version
     >          >> of getThreadAllocatedBytes(long []) calls
     >          >> verifyThreadAllocatedMemory(long []), which checks inline to 
make sure
     >          >> thread allocated memory is supported, then calls
     >          >> isThreadAllocatedMemoryEnabled() to verify that it's enabled.
     >          >> isThreadAllocatedMemoryEnabled() duplicates (!) the support 
check and
     >          >> returns the enabled flag. I removed the redundant check in 
the new
     >          >> version.
     >          >>
     >          >>
     >          >>         You're of course correct about the back-to-back 
check.
     >          >> Application code can't know when the runtime will hijack a 
thread for
     >          >> its own purposes. I've removed the check.
     >          >>
     >          >>
     >          >>         Paul
     >          >>
     >          >>
     >          >>         On 9/13/19, 12:50 AM, "David 
Holmes"<david.hol...@oracle.com>
     >          >> <mailto:david.hol...@oracle.com>  wrote:
     >          >>
     >          >>
     >          >>              Hi Paul,
     >          >>
     >          >>
     >          >>              On 13/09/2019 10:29 am, Hohensee, Paul wrote:
     >          >>
     >          >>              > Thanks for clarifying the review rules. Would 
someone
     >          >> from the
     >          >>
     >          >>              > serviceability team please review? New webrev 
at
     >          >>
     >          >>              >
     >          >>
     >          >>              
>http://cr.openjdk.java.net/~phh/8207266/webrev.07/
     >          >>
     >          >>
     >          >>              One aspect of the functional change needs 
clarification
     >          >> for me - and
     >          >>
     >          >>              apologies if this has been covered in the past. 
It seems
     >          >> to me that
     >          >>
     >          >>              currently we only check 
isThreadAllocatedMemorySupported
     >          >> for these
     >          >>
     >          >>              operations, but if I read things correctly the 
updated
     >          >> code additionally
     >          >>
     >          >>              checks isThreadAllocatedMemoryEnabled, which is 
a
     >          >> behaviour change not
     >          >>
     >          >>              mentioned in the CSR.
     >          >>
     >          >>
     >          >>              > I didn’t disturb the existing checks in the 
test, just
     >          >> added code to
     >          >>
     >          >>              > check the result of 
getThreadAllocatedBytes(long) on a
     >          >> non-current
     >          >>
     >          >>              > thread, plus the back-to-back no-allocation 
checks. The
     >          >> former wasn’t
     >          >>
     >          >>              > needed before because 
getThreadAllocatedBytes(long) was
     >          >> just a wrapper
     >          >>
     >          >>              > around getThreadAllocatedBytes(long []). This 
patch
     >          >> changes that, so I
     >          >>
     >          >>              > added a separate test. The latter is supposed 
to fail
     >          >> if there’s object
     >          >>
     >          >>              > allocation on calls to 
getCurrentThreadAllocatedBytes and
     >          >>
     >          >>              > getThreadAllocatedBytes(long). I.e., a 
feature, not a
     >          >> bug, because
     >          >>
     >          >>              > accumulation of transient small objects can 
be a
     >          >> performance problem.
     >          >>
     >          >>              > Thanks to your review, I noticed that the 
back-to-back
     >          >> check on the
     >          >>
     >          >>              > current thread was using 
getThreadAllocatedBytes(long)
     >          >> instead of
     >          >>
     >          >>              > getCurrentThreadAllocatedBytes and fixed it. 
I also
     >          >> removed all
     >          >>
     >          >>              > instances of “TEST FAILED: “.
     >          >>
     >          >>
     >          >>              The back-to-back check is not valid in general. 
You don't
     >          >> know if the
     >          >>
     >          >>              first check might trigger some class loading on 
the
     >          >> return path after it
     >          >>
     >          >>              has obtained the first memory value. The check 
might also
     >          >> fail if using
     >          >>
     >          >>              JVMCI and some compilation related activity 
occurs in the
     >          >> current thread
     >          >>
     >          >>              on the second call. Also with the introduction 
of
     >          >> handshakes its
     >          >>
     >          >>              possible the current thread might hit a 
safepoint checks
     >          >> that results in
     >          >>
     >          >>              it executing a handshake operation that performs
     >          >> allocation. Potentially
     >          >>
     >          >>              there could be numerous non-deterministic 
actions that
     >          >> might occur
     >          >>
     >          >>              leading to unanticipated allocation.
     >          >>
     >          >>
     >          >>              I understand what you want to test here, I just 
don't
     >          >> think it is
     >          >>
     >          >>              reliably doable.
     >          >>
     >          >>
     >          >>              Thanks,
     >          >>
     >          >>              David
     >          >>
     >          >>              -----
     >          >>
     >          >>
     >          >>              >
     >          >>
     >          >>              > Paul
     >          >>
     >          >>              >
     >          >>
     >          >>              > *From: *Mandy Chung<mandy.ch...@oracle.com>
     >          >> <mailto:mandy.ch...@oracle.com>
     >          >>
     >          >>              > *Date: *Thursday, September 12, 2019 at 10:09 
AM
     >          >>
     >          >>              > *To: *"Hohensee, Paul"<hohen...@amazon.com>
     >          >> <mailto:hohen...@amazon.com>
     >          >>
     >          >>              > *Cc: *OpenJDK
     >          >> Serviceability<serviceability-dev@openjdk.java.net>
     >          >> <mailto:serviceability-dev@openjdk.java.net>,
     >          >>
     >          >>              >"hotspot-gc-...@openjdk.java.net"
     >          >> <mailto:hotspot-gc-...@openjdk.java.net>
     >          >> <hotspot-gc-...@openjdk.java.net>
     >          >> <mailto:hotspot-gc-...@openjdk.java.net>
     >          >>
     >          >>              > *Subject: *Re: RFR (M): 8207266:
     >          >> ThreadMXBean::getThreadAllocatedBytes()
     >          >>
     >          >>              > can be quicker for self thread
     >          >>
     >          >>              >
     >          >>
     >          >>              > On 9/3/19 12:38 PM, Hohensee, Paul wrote:
     >          >>
     >          >>              >
     >          >>
     >          >>              >     Minor update in new
     >          >> webrevhttp://cr.openjdk.java.net/~phh/8207266/webrev.05/.
     >          >>
     >          >>              >
     >          >>
     >          >>              >
     >          >>
     >          >>              > I only reviewed the library side 
implementation that
     >          >> looks good.  I
     >          >>
     >          >>              > expect the serviceability team to review the 
test and
     >          >> hotspot change.
     >          >>
     >          >>              >
     >          >>
     >          >>              >
     >          >>
     >          >>              >     Need a confirmatory review to push this. 
If I
     >          >> understand the rules correctly, it doesn't need a Reviewer 
review
     >          >> since Mandy's already reviewed it, it just needs a Committer 
review.
     >          >>
     >          >>              >
     >          >>
     >          >>              >
     >          >>
     >          >>              > You need another reviewer to advice the 
following
     >          >> because I was not
     >          >>
     >          >>              > close to the ThreadsList work.
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2087   ThreadsListHandle tlh;
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2088   JavaThread* java_thread =
     >          >> tlh.list()->find_JavaThread_from_java_tid(thread_id);
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2089
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2090   if (java_thread != NULL) {
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2091     return 
java_thread->cooked_allocated_bytes();
     >          >>
     >          >>              >
     >          >>
     >          >>              > 2092   }
     >          >>
     >          >>              >
     >          >>
     >          >>              > This looks right to me.
     >          >>
     >          >>              >
     >          >>
     >          >>              >
     >          >> 
test/jdk/com/sun/management/ThreadMXBean/ThreadAllocatedMemory.java
     >          >>
     >          >>              >
     >          >>
     >          >>              > -                "ThreadAllocatedMemory is 
expected to
     >          >> be disabled");
     >          >>
     >          >>              >
     >          >>
     >          >>              > +                "TEST FAILED: 
ThreadAllocatedMemory is
     >          >> expected to be
     >          >>
     >          >>              > disabled");
     >          >>
     >          >>              >
     >          >>
     >          >>              > Prepending "TEST FAILED" in exception message 
(in
     >          >> several places)
     >          >>
     >          >>              >
     >          >>
     >          >>              > seems redundant since such RuntimeException 
is thrown
     >          >> and expected
     >          >>
     >          >>              >
     >          >>
     >          >>              > a test failure.
     >          >>
     >          >>              >
     >          >>
     >          >>              > +        // back-to-back calls shouldn't 
allocate any
     >          >> memory
     >          >>
     >          >>              >
     >          >>
     >          >>              > +        size = 
mbean.getThreadAllocatedBytes(id);
     >          >>
     >          >>              >
     >          >>
     >          >>              > +        size1 = 
mbean.getThreadAllocatedBytes(id);
     >          >>
     >          >>              >
     >          >>
     >          >>              > +        if (size1 != size) {
     >          >>
     >          >>              >
     >          >>
     >          >>              > Is there anything in the test can do to help 
guarantee
     >          >> this? I didn't
     >          >>
     >          >>              >
     >          >>
     >          >>              > closely review this test.  The main thing I 
advice is
     >          >> to improve
     >          >>
     >          >>              >
     >          >>
     >          >>              > the reliability of this test.  Put it in 
another way,
     >          >> we want to
     >          >>
     >          >>              >
     >          >>
     >          >>              > ensure that this test change will pass all 
the time in
     >          >> various
     >          >>
     >          >>              >
     >          >>
     >          >>              > test configuration.
     >          >>
     >          >>              >
     >          >>
     >          >>              > Mandy
     >          >>
     >          >>              >
     >          >>
     >          >>
     >          >>
     >          >>
     >          >>
     >
     >
     >
     >

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