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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