RFR(L) 8153224 Monitor deflation prolong safepoints (CR11/v2.11/14-for-jdk15)
Daniel D. Daugherty
daniel.daugherty at oracle.com
Mon May 11 13:43:38 UTC 2020
Hi David,
Thanks for closing the loop on my CR reply. I'll be making these
changes after I rebase to jdk-15+22 later today...
Dan
On 5/11/20 6:06 AM, David Holmes wrote:
> Hi Dan,
>
> On 9/05/2020 1:26 am, Daniel D. Daugherty wrote:
>> Hi David,
>>
>> Thanks for the fast re-review!!
>>
>>
>> On 5/8/20 2:32 AM, David Holmes wrote:
>>> Hi Dan,
>>>
>>> On 8/05/2020 3:08 am, Daniel D. Daugherty wrote:
>>>> Greetings,
>>>>
>>>> I have made changes to the Async Monitor Deflation code in response to
>>>> the CR10/v2.10/13-for-jdk15 code review cycle and DaCapo-h2 perf
>>>> testing.
>>>> Thanks to Erik O., Robbin and David H. for their OpenJDK reviews in
>>>> the
>>>> v2.10 round! Thanks to Eric C. for his help in isolating the DaCapo-h2
>>>> performance regression.
>>>>
>>>> With the removal of ref_counting and the ObjectMonitorHandle class,
>>>> the
>>>> Async Monitor Deflation project is now closer to Carsten's original
>>>> prototype. While ref_counting gave us ObjectMonitor* safety
>>>> enforced by
>>>> code, I saw a ~22.8% slow down with -XX:-AsyncDeflateIdleMonitors
>>>> ("off"
>>>> mode). The slow down with "on" mode -XX:+AsyncDeflateIdleMonitors
>>>> is ~17%.
>>>
>>> Great work!
>>
>> Thanks! Eric C. was very helpful in helping me figure out what was
>> going on with
>> DaCapo-h2.
>>
>>
>>>
>>>> I have attached the change list from CR10 to CR11 instead of
>>>> putting it in
>>>> the body of this email. I've also added a link to the
>>>> CR10-to-CR11-changes
>>>> file to the webrevs so it should be easy to find.
>>>>
>>>> Main bug URL:
>>>>
>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>
>>>> The project is currently baselined on jdk-15+21.
>>>>
>>>> Here's the full webrev URL for those folks that want to see all of the
>>>> current Async Monitor Deflation code in one go (v2.11 full):
>>>>
>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/14-for-jdk15%2b21.v2.11.full/
>>>>
>>>>
>>>> Some folks might want to see just what has changed since the last
>>>> review
>>>> cycle so here's a webrev for that (v2.11 inc):
>>>>
>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/14-for-jdk15%2b21.v2.11.inc/
>>>
>>>
>>>
>>>
>>> I looked at the incremental and also at the full webrev (which I
>>> found much easier to read this time round :) ).
>>
>> I was going to recommend the full webrev over the incremental, but I
>> didn't
>> because I wasn't sure if I was too close to be objective...
>>
>>
>>> I only have a couple of minor nits.
>>>
>>> src/hotspot/share/prims/jvmtiEnvBase.cpp
>>>
>>> Not really related to your change other than your comment wording
>>> made me think:
>>>
>>> 656 // The ObjectMonitor* can't be async deflated since we are
>>> either
>>> 657 // at a safepoint or the calling thread is operating on
>>> itself so
>>> 658 // it cannot leave the underlying wait()/enter() call.
>>>
>>> I don't see how we can be operating on the current thread in that
>>> way - if a thread is in enter or wait then how can it be executing
>>> this JVM TI code? If this code is executing in the current thread
>>> then AFAICS it must find that it is not in enter nor in wait. Put
>>> another way if executing in the current thread then we must find
>>> pending_monitor and waiting_monitor to be NULL, so deflation is a
>>> non-issue.
>>
>> For context, we're talking about this JVM/TI function:
>>
>> L650: JvmtiEnvBase::get_current_contended_monitor(JavaThread
>> *java_thread, jobject *monitor_ptr) {
>
> Yes
>
>> being called by this function:
>>
>> src/hotspot/share/runtime/objectMonitor.cpp:
>>
>> L243: bool ObjectMonitor::enter(TRAPS) {
>>
>> or this function:
>>
>> L1304: void ObjectMonitor::wait(jlong millis, bool
>> interruptible, TRAPS) {
>
> Okay this is an indirect path to the code ...
>
>>
>> For the ObjectMonitor::enter() case, current_pending_monitor is set
>> here:
>>
>> L323: Self->set_current_pending_monitor(this);
>>
>> and a JVM/TI event is posted here:
>>
>> L326: if (JvmtiExport::should_post_monitor_contended_enter()) {
>> L327: JvmtiExport::post_monitor_contended_enter(jt, this);
>>
>> and the remainder of the enter protocol is handled here (including
>> blocking
>> on entry to the monitor):
>>
>> L345: EnterI(THREAD);
>
> Yes
>
>> and the current_pending_monitor is cleared here:
>>
>> L360: Self->set_current_pending_monitor(NULL);
>
> Yes
>
>>
>> For the ObjectMonitor::wait() case, current_waiting_monitor is set here:
>>
>> L1340: jt->set_current_waiting_monitor(this);
>>
>> and a JVM/TI event is posted here:
>>
>> L1450: if (JvmtiExport::should_post_monitor_waited()) {
>> L1451: JvmtiExport::post_monitor_waited(jt, this, ret ==
>> OS_TIMEOUT);
>>
>> and the current_waiting_monitor is cleared here:
>>
>> L1501: jt->set_current_waiting_monitor(NULL);
>
> Yes
>
>>
>> The event handlers for both of the above mentioned events can call
>> JVM/TI GetCurrentContendedMonitor() which gets us into
>> JvmtiEnvBase::get_current_contended_monitor().
>
> Okay I see that path now - thanks.
>
>>
>>> Ditto for the similar comments in
>>> - JvmtiEnvBase::get_locked_objects_in_frame.
>>
>> The event handlers can call JVM/TI GetOwnedMonitorInfo() which gets
>> us into
>> JvmtiEnvBase::get_locked_objects_in_frame().
>>
>>
>>> - javaVFrame::locked_monitors (src/hotspot/share/runtime/vframe.cpp )
>>>
>>> but in these cases it isn't a matter of being in enter() but that
>>> you have called enter() and can't call exit() while in this code so
>>> the monitor can't be deflated as you own it.
>>
>> I _think_ there's a way for native code to call into M&M functions to
>> get us into this code, but you're right that the more likely called by
>> current thread case is that the current thread enters the monitor and
>> then calls the M&M function before exiting the monitor.
>>
>> Here's the vframe.cpp comment:
>>
>> L125: // The ObjectMonitor* can't be async deflated since we
>> are either
>> L126: // at a safepoint or the calling thread is operating on
>> itself so
>> L127: // it cannot leave the underlying wait()/enter() call.
>>
>> I could change that last line to this:
>>
>> L127: // it cannot exit the ObjectMonitor so it remains busy.
>
> That sounds good to me.
>>
>>> ---
>>>
>>> src/hotspot/share/runtime/objectMonitor.inline.hpp
>>>
>>> ! inline void ObjectMonitor::clear_using_JT() {
>>> ! // Unlike other *_using_JT() functions, we cannot assert
>>> ! // AsyncDeflateIdleMonitors or Thread::current()->is_Java_thread()
>>> ! // because clear() calls this function for the rest of its checks.
>>>
>>> In that case if this can be called by a non-JT then it should be
>>> renamed IMO - perhaps clear_common()?
>>
>> I like that idea. If I rename it, then I can drop that 3-line comment
>> right?
>
> Absolutely! :)
>
> Thanks,
> David
> -----
>
>>
>>
>>> ---
>>>
>>> That's it. Nothing further from me.
>>
>> Thanks again for the re-review (and the many previous reviews)!
>>
>>
>>> Again great work!
>>
>> Thanks!
>>
>> Dan
>>
>>
>>>
>>> Thanks,
>>> David
>>> -----
>>>
>>>>
>>>> Because of the removal of ref_counting and the ObjectMonitorHandle
>>>> class, the
>>>> incremental webrev is a bit noisier than I would have preferred.
>>>>
>>>>
>>>> The OpenJDK wiki has NOT YET been updated for this round of changes:
>>>>
>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>
>>>> The jdk-15+21 based v2.11 version of the patch has been thru Mach5
>>>> tier[1-6]
>>>> testing on Oracle's usual set of platforms. Mach5 tier[78] are
>>>> still running.
>>>> I'm running the v2.11 patch through my usual set of stress testing on
>>>> Linux-X64 and macOSX.
>>>>
>>>> I'm planning to do a SPECjbb2015, DaCapo-h2 and volano round on the
>>>> CR11/v2.11/14-for-jdk15 bits.
>>>>
>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>
>>>> Dan
>>>>
>>>>
>>>> On 2/26/20 5:22 PM, Daniel D. Daugherty wrote:
>>>>> Greetings,
>>>>>
>>>>> I have made changes to the Async Monitor Deflation code in
>>>>> response to
>>>>> the CR9/v2.09/12-for-jdk14 code review cycle. Thanks to Robbin and
>>>>> Erik O.
>>>>> for their comments in this round!
>>>>>
>>>>> With the extraction and push of {8235931,8236035,8235795} to
>>>>> JDK15, the
>>>>> Async Monitor Deflation code is back to "just" async deflation
>>>>> changes!
>>>>>
>>>>> I have attached the change list from CR9 to CR10 instead of
>>>>> putting it in
>>>>> the body of this email. I've also added a link to the
>>>>> CR9-to-CR10-changes
>>>>> file to the webrevs so it should be easy to find.
>>>>>
>>>>> Main bug URL:
>>>>>
>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>
>>>>> The project is currently baselined on jdk-15+11.
>>>>>
>>>>> Here's the full webrev URL for those folks that want to see all of
>>>>> the
>>>>> current Async Monitor Deflation code in one go (v2.10 full):
>>>>>
>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/13-for-jdk15+11.v2.10.full/
>>>>>
>>>>>
>>>>> Some folks might want to see just what has changed since the last
>>>>> review
>>>>> cycle so here's a webrev for that (v2.10 inc):
>>>>>
>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/13-for-jdk15+11.v2.10.inc/
>>>>>
>>>>>
>>>>> Since we backed out the HandshakeAfterDeflateIdleMonitors option
>>>>> and the
>>>>> C2 ref_count changes and updated the copyright years, the "inc"
>>>>> webrev has
>>>>> a bit more noise in it than usual. Sorry about that!
>>>>>
>>>>> The OpenJDK wiki has been updated for this round of changes:
>>>>>
>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>
>>>>> The jdk-15+11 based v2.10 version of the patch has been thru Mach5
>>>>> tier[1-7]
>>>>> testing on Oracle's usual set of platforms. Mach5 tier8 is still
>>>>> running.
>>>>> I'm running the v2.10 patch through my usual set of stress testing on
>>>>> Linux-X64 and macOSX.
>>>>>
>>>>> I'm planning to do a SPECjbb2015 round on the
>>>>> CR10/v2.20/13-for-jdk15 bits.
>>>>>
>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>
>>>>> Dan
>>>>>
>>>>>
>>>>> On 2/4/20 9:41 AM, Daniel D. Daugherty wrote:
>>>>>> Greetings,
>>>>>>
>>>>>> This project is no longer targeted to JDK14 so this is NOT an
>>>>>> urgent code
>>>>>> review request.
>>>>>>
>>>>>> I've extracted the following three fixes from the Async Monitor
>>>>>> Deflation
>>>>>> project code:
>>>>>>
>>>>>> JDK-8235931 add OM_CACHE_LINE_SIZE and use smaller size on
>>>>>> SPARCv9 and X64
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8235931
>>>>>>
>>>>>> JDK-8236035 refactor ObjectMonitor::set_owner() and _owner
>>>>>> field setting
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8236035
>>>>>>
>>>>>> JDK-8235795 replace monitor list
>>>>>> mux{Acquire,Release}(&gListLock) with spin locks
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8235795
>>>>>>
>>>>>> Each of these has been reviewed separately and will be pushed to
>>>>>> JDK15
>>>>>> in the near future (possibly by the end of this week). Of course,
>>>>>> there
>>>>>> were improvements during these review cycles and the purpose of this
>>>>>> e-mail is to provided updated webrevs for this fix
>>>>>> (CR9/v2.09/12-for-jdk14)
>>>>>> within the revised context provided by {8235931, 8236035, 8235795}.
>>>>>>
>>>>>> Main bug URL:
>>>>>>
>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>
>>>>>> The project is currently baselined on jdk-14+34.
>>>>>>
>>>>>> Here's the full webrev URL for those folks that want to see all
>>>>>> of the
>>>>>> current Async Monitor Deflation code along with {8235931,
>>>>>> 8236035, 8235795}
>>>>>> in one go (v2.09b full):
>>>>>>
>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/12-for-jdk14.v2.09b.full/
>>>>>>
>>>>>>
>>>>>> Compare the open.patch file in 12-for-jdk14.v2.09.full and
>>>>>> 12-for-jdk14.v2.09b.full
>>>>>> using your favorite file comparison/merge tool to see how Async
>>>>>> Monitor Deflation
>>>>>> evolved due to {8235931, 8236035, 8235795}.
>>>>>>
>>>>>> Some folks might want to see just the Async Monitor Deflation
>>>>>> code on top of
>>>>>> {8235931, 8236035, 8235795} so here's a webrev for that (v2.09b
>>>>>> inc):
>>>>>>
>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/12-for-jdk14.v2.09b.inc/
>>>>>>
>>>>>>
>>>>>> These webrevs have gone thru several Mach5 Tier[1-8] runs along with
>>>>>> my usual stress testing and SPECjbb2015 testing and there aren't any
>>>>>> surprises relative to CR9/v2.09/12-for-jdk14.
>>>>>>
>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>
>>>>>> Dan
>>>>>>
>>>>>>
>>>>>> On 12/11/19 3:41 PM, Daniel D. Daugherty wrote:
>>>>>>> Greetings,
>>>>>>>
>>>>>>> I have made changes to the Async Monitor Deflation code in
>>>>>>> response to
>>>>>>> the CR8/v2.08/11-for-jdk14 code review cycle. Thanks to David
>>>>>>> H., Robbin
>>>>>>> and Erik O. for their comments!
>>>>>>>
>>>>>>> This project is no longer targeted to JDK14 so this is NOT an
>>>>>>> urgent code
>>>>>>> review request. The primary purpose of this webrev is simply to
>>>>>>> close the
>>>>>>> CR8/v2.08/11-for-jdk14 code review loop and to let folks see how
>>>>>>> I resolved
>>>>>>> the code review comments from that round.
>>>>>>>
>>>>>>> Most of the comments in the CR8/v2.08/11-for-jdk14 code review
>>>>>>> cycle were
>>>>>>> on the monitor list changes so I'm going to take a look at
>>>>>>> extracting those
>>>>>>> changes into a standalone patch. Switching from
>>>>>>> Thread::muxAcquire(&gListLock)
>>>>>>> and Thread::muxRelease(&gListLock) to finer grained internal
>>>>>>> spin locks needs
>>>>>>> to be thoroughly reviewed and the best way to do that is
>>>>>>> separately from the
>>>>>>> Async Monitor Deflation changes. Thanks to Coleen for suggesting
>>>>>>> doing this
>>>>>>> extraction earlier.
>>>>>>>
>>>>>>> I have attached the change list from CR8 to CR9 instead of
>>>>>>> putting it in
>>>>>>> the body of this email. I've also added a link to the
>>>>>>> CR8-to-CR9-changes
>>>>>>> file to the webrevs so it should be easy to find.
>>>>>>>
>>>>>>> Main bug URL:
>>>>>>>
>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>
>>>>>>> The project is currently baselined on jdk-14+26.
>>>>>>>
>>>>>>> Here's the full webrev URL for those folks that want to see all
>>>>>>> of the
>>>>>>> current Async Monitor Deflation code in one go (v2.09 full):
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/12-for-jdk14.v2.09.full/
>>>>>>>
>>>>>>>
>>>>>>> Some folks might want to see just what has changed since the
>>>>>>> last review
>>>>>>> cycle so here's a webrev for that (v2.09 inc):
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/12-for-jdk14.v2.09.inc/
>>>>>>>
>>>>>>>
>>>>>>> The OpenJDK wiki has NOT yet been updated for this round of
>>>>>>> changes:
>>>>>>>
>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>
>>>>>>>
>>>>>>> The jdk-14+26 based v2.09 version of the patch has been thru
>>>>>>> Mach5 tier[1-7]
>>>>>>> testing on Oracle's usual set of platforms. Mach5 tier8 is still
>>>>>>> running.
>>>>>>> A slightly older version of the v2.09 patch has also been
>>>>>>> through my usual
>>>>>>> set of stress testing on Linux-X64 and macOSX with the addition
>>>>>>> of Robbin's
>>>>>>> "MoCrazy 1024" test running in parallel on Linux-X64 with the
>>>>>>> other tests in
>>>>>>> my lab. The "MoCrazy 1024" has been going for > 5 days and 6700+
>>>>>>> iterations
>>>>>>> without any failures.
>>>>>>>
>>>>>>> I'm planning to do a SPECjbb2015 round on the
>>>>>>> CR9/v2.09/12-for-jdk14 bits.
>>>>>>>
>>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>>
>>>>>>> Dan
>>>>>>>
>>>>>>>
>>>>>>> On 11/4/19 4:03 PM, Daniel D. Daugherty wrote:
>>>>>>>> Greetings,
>>>>>>>>
>>>>>>>> I have made changes to the Async Monitor Deflation code in
>>>>>>>> response to
>>>>>>>> the CR7/v2.07/10-for-jdk14 code review cycle. Thanks to David
>>>>>>>> H., Robbin
>>>>>>>> and Erik O. for their comments!
>>>>>>>>
>>>>>>>> JDK14 Rampdown phase one is coming on Dec. 12, 2019 and the
>>>>>>>> Async Monitor
>>>>>>>> Deflation project needs to push before Nov. 12, 2019 in order
>>>>>>>> to allow
>>>>>>>> for sufficient bake time for such a big change. Nov. 12 is
>>>>>>>> _next_ Tuesday
>>>>>>>> so we have 8 days from today to finish this code review cycle
>>>>>>>> and push
>>>>>>>> this code for JDK14.
>>>>>>>>
>>>>>>>> Carsten and Roman! Time for you guys to chime in again on the
>>>>>>>> code reviews.
>>>>>>>>
>>>>>>>> I have attached the change list from CR7 to CR8 instead of
>>>>>>>> putting it in
>>>>>>>> the body of this email. I've also added a link to the
>>>>>>>> CR7-to-CR8-changes
>>>>>>>> file to the webrevs so it should be easy to find.
>>>>>>>>
>>>>>>>> Main bug URL:
>>>>>>>>
>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>
>>>>>>>> The project is currently baselined on jdk-14+21.
>>>>>>>>
>>>>>>>> Here's the full webrev URL for those folks that want to see all
>>>>>>>> of the
>>>>>>>> current Async Monitor Deflation code in one go (v2.08 full):
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/11-for-jdk14.v2.08.full
>>>>>>>>
>>>>>>>>
>>>>>>>> Some folks might want to see just what has changed since the
>>>>>>>> last review
>>>>>>>> cycle so here's a webrev for that (v2.08 inc):
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/11-for-jdk14.v2.08.inc/
>>>>>>>>
>>>>>>>>
>>>>>>>> The OpenJDK wiki did not need any changes for this round:
>>>>>>>>
>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>
>>>>>>>>
>>>>>>>> The jdk-14+21 based v2.08 version of the patch has been thru
>>>>>>>> Mach5 tier[1-8]
>>>>>>>> testing on Oracle's usual set of platforms. It has also been
>>>>>>>> through my usual
>>>>>>>> set of stress testing on Linux-X64, macOSX and Solaris-X64 with
>>>>>>>> the addition
>>>>>>>> of Robbin's "MoCrazy 1024" test running in parallel with the
>>>>>>>> other tests in
>>>>>>>> my lab. Some testing is still running, but so far there are no
>>>>>>>> new regressions.
>>>>>>>>
>>>>>>>> I have not yet done a SPECjbb2015 round on the
>>>>>>>> CR8/v2.08/11-for-jdk14 bits.
>>>>>>>>
>>>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>>>
>>>>>>>> Dan
>>>>>>>>
>>>>>>>>
>>>>>>>> On 10/17/19 5:50 PM, Daniel D. Daugherty wrote:
>>>>>>>>> Greetings,
>>>>>>>>>
>>>>>>>>> The Async Monitor Deflation project is reaching the end game.
>>>>>>>>> I have no
>>>>>>>>> changes planned for the project at this time so all that is
>>>>>>>>> left is code
>>>>>>>>> review and any changes that results from those reviews.
>>>>>>>>>
>>>>>>>>> Carsten and Roman! Time for you guys to chime in again on the
>>>>>>>>> code reviews.
>>>>>>>>>
>>>>>>>>> I have attached the list of fixes from CR6 to CR7 instead of
>>>>>>>>> putting it
>>>>>>>>> in the main body of this email.
>>>>>>>>>
>>>>>>>>> Main bug URL:
>>>>>>>>>
>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>
>>>>>>>>> The project is currently baselined on jdk-14+19.
>>>>>>>>>
>>>>>>>>> Here's the full webrev URL for those folks that want to see
>>>>>>>>> all of the
>>>>>>>>> current Async Monitor Deflation code in one go (v2.07 full):
>>>>>>>>>
>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/10-for-jdk14.v2.07.full
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Some folks might want to see just what has changed since the
>>>>>>>>> last review
>>>>>>>>> cycle so here's a webrev for that (v2.07 inc):
>>>>>>>>>
>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/10-for-jdk14.v2.07.inc/
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> The OpenJDK wiki has been updated to match the
>>>>>>>>> CR7/v2.07/10-for-jdk14 changes:
>>>>>>>>>
>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> The jdk-14+18 based v2.07 version of the patch has been thru
>>>>>>>>> Mach5 tier[1-8]
>>>>>>>>> testing on Oracle's usual set of platforms. It has also been
>>>>>>>>> through my usual
>>>>>>>>> set of stress testing on Linux-X64, macOSX and Solaris-X64
>>>>>>>>> with the addition
>>>>>>>>> of Robbin's "MoCrazy 1024" test running in parallel with the
>>>>>>>>> other tests in
>>>>>>>>> my lab.
>>>>>>>>>
>>>>>>>>> The jdk-14+19 based v2.07 version of the patch has been thru
>>>>>>>>> Mach5 tier[1-3]
>>>>>>>>> test on Oracle's usual set of platforms. Mach5 tier[4-8] are
>>>>>>>>> in process.
>>>>>>>>>
>>>>>>>>> I did another round of SPECjbb2015 testing in Oracle's Aurora
>>>>>>>>> Performance lab
>>>>>>>>> using using their tuned SPECjbb2015 Linux-X64 G1 configs:
>>>>>>>>>
>>>>>>>>> - "base" is jdk-14+18
>>>>>>>>> - "v2.07" is the latest version and includes C2
>>>>>>>>> inc_om_ref_count() support
>>>>>>>>> on LP64 X64 and the new
>>>>>>>>> HandshakeAfterDeflateIdleMonitors option
>>>>>>>>> - "off" is with -XX:-AsyncDeflateIdleMonitors specified
>>>>>>>>> - "handshake" is with
>>>>>>>>> -XX:+HandshakeAfterDeflateIdleMonitors specified
>>>>>>>>>
>>>>>>>>> hbIR hbIR
>>>>>>>>> (max attempted) (settled) max-jOPS critical-jOPS runtime
>>>>>>>>> --------------- --------- -------- ------------- -------
>>>>>>>>> 34282.00 30635.90 28831.30 20969.20 3841.30 base
>>>>>>>>> 34282.00 30973.00 29345.80 21025.20 3964.10 v2.07
>>>>>>>>> 34282.00 31105.60 29174.30 21074.00 3931.30
>>>>>>>>> v2.07_handshake
>>>>>>>>> 34282.00 30789.70 27151.60 19839.10 3850.20
>>>>>>>>> v2.07_off
>>>>>>>>>
>>>>>>>>> - The Aurora Perf comparison tool reports:
>>>>>>>>>
>>>>>>>>> Comparison max-jOPS critical-jOPS
>>>>>>>>> ---------------------- --------------------
>>>>>>>>> --------------------
>>>>>>>>> base vs 2.07 +1.78% (s, p=0.000) +0.27%
>>>>>>>>> (ns, p=0.790)
>>>>>>>>> base vs 2.07_handshake +1.19% (s, p=0.007) +0.58%
>>>>>>>>> (ns, p=0.536)
>>>>>>>>> base vs 2.07_off -5.83% (ns, p=0.394) -5.39%
>>>>>>>>> (ns, p=0.347)
>>>>>>>>>
>>>>>>>>> (s) - significant (ns) - not-significant
>>>>>>>>>
>>>>>>>>> - For historical comparison, the Aurora Perf comparision tool
>>>>>>>>> reported for v2.06 with a baseline of jdk-13+31:
>>>>>>>>>
>>>>>>>>> Comparison max-jOPS critical-jOPS
>>>>>>>>> ---------------------- --------------------
>>>>>>>>> --------------------
>>>>>>>>> base vs 2.06 -0.32% (ns, p=0.345) +0.71%
>>>>>>>>> (ns, p=0.646)
>>>>>>>>> base vs 2.06_off +0.49% (ns, p=0.292) -1.21%
>>>>>>>>> (ns, p=0.481)
>>>>>>>>>
>>>>>>>>> (s) - significant (ns) - not-significant
>>>>>>>>>
>>>>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>>>>
>>>>>>>>> Dan
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 8/28/19 5:02 PM, Daniel D. Daugherty wrote:
>>>>>>>>>> Greetings,
>>>>>>>>>>
>>>>>>>>>> The Async Monitor Deflation project has rebased to JDK14 so
>>>>>>>>>> it's time
>>>>>>>>>> for our first code review in that new context!!
>>>>>>>>>>
>>>>>>>>>> I've been focused on changing the monitor list management
>>>>>>>>>> code to be
>>>>>>>>>> lock-free in order to make SPECjbb2015 happier. Of course
>>>>>>>>>> with a change
>>>>>>>>>> like that, it takes a while to chase down all the new and
>>>>>>>>>> wonderful
>>>>>>>>>> races. At this point, I have the code back to the same
>>>>>>>>>> stability that
>>>>>>>>>> I had with CR5/v2.05/8-for-jdk13.
>>>>>>>>>>
>>>>>>>>>> To lay the ground work for this round of review, I pushed the
>>>>>>>>>> following
>>>>>>>>>> two fixes to jdk/jdk earlier today:
>>>>>>>>>>
>>>>>>>>>> JDK-8230184 rename, whitespace, indent and comments
>>>>>>>>>> changes in preparation
>>>>>>>>>> for lock free Monitor lists
>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8230184
>>>>>>>>>>
>>>>>>>>>> JDK-8230317 serviceability/sa/ClhsdbPrintStatics.java
>>>>>>>>>> fails after 8230184
>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8230317
>>>>>>>>>>
>>>>>>>>>> I have attached the list of fixes from CR5 to CR6 instead of
>>>>>>>>>> putting
>>>>>>>>>> in the main body of this email.
>>>>>>>>>>
>>>>>>>>>> Main bug URL:
>>>>>>>>>>
>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>
>>>>>>>>>> The project is currently baselined on jdk-14+11 plus the
>>>>>>>>>> fixes for
>>>>>>>>>> JDK-8230184 and JDK-8230317.
>>>>>>>>>>
>>>>>>>>>> Here's the full webrev URL for those folks that want to see
>>>>>>>>>> all of the
>>>>>>>>>> current Async Monitor Deflation code in one go (v2.06 full):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.06.full/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The primary focus of this review cycle is on the lock-free
>>>>>>>>>> Monitor List
>>>>>>>>>> management changes so here's a webrev for just that patch
>>>>>>>>>> (v2.06c):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.06c.inc/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The secondary focus of this review cycle is on the bug fixes
>>>>>>>>>> that have
>>>>>>>>>> been made since CR5/v2.05/8-for-jdk13 so here's a webrev for
>>>>>>>>>> just that
>>>>>>>>>> patch (v2.06b):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.06b.inc/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The third and final bucket for this review cycle is the
>>>>>>>>>> rename, whitespace,
>>>>>>>>>> indent and comments changes made in preparation for lock free
>>>>>>>>>> Monitor list
>>>>>>>>>> management. Almost all of that was extracted into JDK-8230184
>>>>>>>>>> for the
>>>>>>>>>> baseline so this bucket now has just a few comment changes
>>>>>>>>>> relative to
>>>>>>>>>> CR5/v2.05/8-for-jdk13. Here's a webrev for the remainder
>>>>>>>>>> (v2.06a):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.06a.inc/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Some folks might want to see just what has changed since the
>>>>>>>>>> last review
>>>>>>>>>> cycle so here's a webrev for that (v2.06 inc):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.06.inc/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Last, but not least, some folks might want to see the code
>>>>>>>>>> before the
>>>>>>>>>> addition of lock-free Monitor List management so here's a
>>>>>>>>>> webrev for
>>>>>>>>>> that (v2.00 -> v2.05):
>>>>>>>>>>
>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/9-for-jdk14.v2.05.inc/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The OpenJDK wiki will need minor updates to match the CR6
>>>>>>>>>> changes:
>>>>>>>>>>
>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> but that should only be changes to describe per-thread list
>>>>>>>>>> async monitor
>>>>>>>>>> deflation being done by the ServiceThread.
>>>>>>>>>>
>>>>>>>>>> (I did update the OpenJDK wiki for the CR5 changes back on
>>>>>>>>>> 2019.08.14)
>>>>>>>>>>
>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-8]
>>>>>>>>>> testing on
>>>>>>>>>> Oracle's usual set of platforms. It has also been through my
>>>>>>>>>> usual set
>>>>>>>>>> of stress testing on Linux-X64, macOSX and Solaris-X64.
>>>>>>>>>>
>>>>>>>>>> I did a bunch of SPECjbb2015 testing in Oracle's Aurora
>>>>>>>>>> Performance lab
>>>>>>>>>> using using their tuned SPECjbb2015 Linux-X64 G1 configs.
>>>>>>>>>> This was using
>>>>>>>>>> this patch baselined on jdk-13+31 (for stability):
>>>>>>>>>>
>>>>>>>>>> hbIR hbIR
>>>>>>>>>> (max attempted) (settled) max-jOPS critical-jOPS runtime
>>>>>>>>>> --------------- --------- -------- ------------- -------
>>>>>>>>>> 34282.00 28837.20 27905.20 19817.40 3658.10 base
>>>>>>>>>> 34965.70 29798.80 27814.90 19959.00 3514.60
>>>>>>>>>> v2.06d
>>>>>>>>>> 34282.00 29100.70 28042.50 19577.00 3701.90
>>>>>>>>>> v2.06d_off
>>>>>>>>>> 34282.00 29218.50 27562.80 19397.30 3657.60
>>>>>>>>>> v2.06d_ocache
>>>>>>>>>> 34965.70 29838.30 26512.40 19170.60 3569.90 v2.05
>>>>>>>>>> 34282.00 28926.10 27734.00 19835.10 3588.40
>>>>>>>>>> v2.05_off
>>>>>>>>>>
>>>>>>>>>> The "off" configs are with -XX:-AsyncDeflateIdleMonitors
>>>>>>>>>> specified and
>>>>>>>>>> the "ocache" config is with 128 byte cache line sizes instead
>>>>>>>>>> of 64 byte
>>>>>>>>>> cache lines sizes. "v2.06d" is the last set of changes that I
>>>>>>>>>> made before
>>>>>>>>>> those changes were distributed into the "v2.06a", "v2.06b"
>>>>>>>>>> and "v2.06c"
>>>>>>>>>> buckets for this review recycle.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>>>>>
>>>>>>>>>> Dan
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On 7/11/19 3:49 PM, Daniel D. Daugherty wrote:
>>>>>>>>>>> Greetings,
>>>>>>>>>>>
>>>>>>>>>>> I've been focused on chasing down and fixing the rare test
>>>>>>>>>>> failures
>>>>>>>>>>> that only pop up rarely. So this round is primarily fixes
>>>>>>>>>>> for races
>>>>>>>>>>> with a few additional fixes that came from Karen's review of
>>>>>>>>>>> CR4.
>>>>>>>>>>> Thanks Karen!
>>>>>>>>>>>
>>>>>>>>>>> I have attached the list of fixes from CR4 to CR5 instead of
>>>>>>>>>>> putting
>>>>>>>>>>> in the main body of this email.
>>>>>>>>>>>
>>>>>>>>>>> Main bug URL:
>>>>>>>>>>>
>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>
>>>>>>>>>>> The project is currently baselined on jdk-13+29. This will
>>>>>>>>>>> likely be
>>>>>>>>>>> the last JDK13 baseline for this project and I'll roll to
>>>>>>>>>>> the JDK14
>>>>>>>>>>> (jdk/jdk) repo soon...
>>>>>>>>>>>
>>>>>>>>>>> Here's the full webrev URL:
>>>>>>>>>>>
>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/8-for-jdk13.full/
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Here's the incremental webrev URL:
>>>>>>>>>>>
>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/8-for-jdk13.inc/
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I have not yet checked the OpenJDK wiki to see if it needs
>>>>>>>>>>> any updates
>>>>>>>>>>> to match the CR5 changes:
>>>>>>>>>>>
>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> (I did update the OpenJDK wiki for the CR4 changes back on
>>>>>>>>>>> 2019.06.26)
>>>>>>>>>>>
>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-3]
>>>>>>>>>>> testing on
>>>>>>>>>>> Oracle's usual set of platforms. Mach5 tier[4-6] is running
>>>>>>>>>>> now and
>>>>>>>>>>> Mach5 tier[78] will follow. I'll kick off the usual stress
>>>>>>>>>>> testing
>>>>>>>>>>> on Linux-X64, macOSX and Solaris-X64 as those machines
>>>>>>>>>>> become available.
>>>>>>>>>>> Since I haven't made any performance changes in this round,
>>>>>>>>>>> I'll only
>>>>>>>>>>> be running SPECjbb2015 to gather the latest monitorinflation
>>>>>>>>>>> logs.
>>>>>>>>>>>
>>>>>>>>>>> Next up:
>>>>>>>>>>>
>>>>>>>>>>> - We're still seeing 4-5% lower performance with SPECjbb2015 on
>>>>>>>>>>> Linux-X64 and we've determined that some of that comes from
>>>>>>>>>>> contention on the gListLock. So I'm going to investigate
>>>>>>>>>>> removing
>>>>>>>>>>> the gListLock. Yes, another lock free set of changes is
>>>>>>>>>>> coming!
>>>>>>>>>>> - Of course, going lock free often causes new races and new
>>>>>>>>>>> failures
>>>>>>>>>>> so that's a good reason for make those changes isolated in
>>>>>>>>>>> their
>>>>>>>>>>> own round (and not holding up CR5/v2.05/8-for-jdk13 anymore).
>>>>>>>>>>> - I finally have a potential fix for the Win* failure with
>>>>>>>>>>> gc/g1/humongousObjects/TestHumongousClassLoader.java
>>>>>>>>>>> but I haven't run it through Mach5 yet so it'll be in the
>>>>>>>>>>> next round.
>>>>>>>>>>> - Some RTM tests were recently re-enabled in Mach5 and I'm
>>>>>>>>>>> seeing some
>>>>>>>>>>> monitor related failures there. I suspect that I need to
>>>>>>>>>>> go take a
>>>>>>>>>>> look at the C2 RTM macro assembler code and look for
>>>>>>>>>>> things that might
>>>>>>>>>>> conflict if Async Monitor Deflation. If you're interested
>>>>>>>>>>> in that kind
>>>>>>>>>>> of issue, then see the macroAssembler_x86.cpp sanity check
>>>>>>>>>>> that I
>>>>>>>>>>> added in this round!
>>>>>>>>>>>
>>>>>>>>>>> Thanks, in advance, for any questions, comments or suggestions.
>>>>>>>>>>>
>>>>>>>>>>> Dan
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 5/26/19 8:30 PM, Daniel D. Daugherty wrote:
>>>>>>>>>>>> Greetings,
>>>>>>>>>>>>
>>>>>>>>>>>> I have a fix for an issue that came up during performance
>>>>>>>>>>>> testing.
>>>>>>>>>>>> Many thanks to Robbin for diagnosing the issue in his
>>>>>>>>>>>> SPECjbb2015
>>>>>>>>>>>> experiments.
>>>>>>>>>>>>
>>>>>>>>>>>> Here's the list of changes from CR3 to CR4. The list is a bit
>>>>>>>>>>>> verbose due to the complexity of the issue, but the changes
>>>>>>>>>>>> themselves are not that big.
>>>>>>>>>>>>
>>>>>>>>>>>> Functional:
>>>>>>>>>>>> - Change SafepointSynchronize::is_cleanup_needed() from
>>>>>>>>>>>> calling
>>>>>>>>>>>> ObjectSynchronizer::is_cleanup_needed() to calling
>>>>>>>>>>>> ObjectSynchronizer::is_safepoint_deflation_needed():
>>>>>>>>>>>> - is_safepoint_deflation_needed() returns the result of
>>>>>>>>>>>> monitors_used_above_threshold() for safepoint based
>>>>>>>>>>>> monitor deflation (!AsyncDeflateIdleMonitors).
>>>>>>>>>>>> - For AsyncDeflateIdleMonitors, it only returns true if
>>>>>>>>>>>> there is a special deflation request, e.g., System.gc()
>>>>>>>>>>>> - This solves a bug where there are a bunch of Cleanup
>>>>>>>>>>>> safepoints that simply request async deflation which
>>>>>>>>>>>> keeps the async JavaThreads from making progress on
>>>>>>>>>>>> their async deflation work.
>>>>>>>>>>>> - Add AsyncDeflationInterval diagnostic option. Description:
>>>>>>>>>>>> Async deflate idle monitors every so many
>>>>>>>>>>>> milliseconds when
>>>>>>>>>>>> MonitorUsedDeflationThreshold is exceeded (0 is off).
>>>>>>>>>>>> - Replace
>>>>>>>>>>>> ObjectSynchronizer::gOmShouldDeflateIdleMonitors() with
>>>>>>>>>>>> ObjectSynchronizer::is_async_deflation_needed():
>>>>>>>>>>>> - is_async_deflation_needed() returns true when
>>>>>>>>>>>> is_async_cleanup_requested() is true or when
>>>>>>>>>>>> monitors_used_above_threshold() is true (but no more
>>>>>>>>>>>> often than
>>>>>>>>>>>> AsyncDeflationInterval).
>>>>>>>>>>>> - if AsyncDeflateIdleMonitors Service_lock->wait() now
>>>>>>>>>>>> waits for
>>>>>>>>>>>> at most GuaranteedSafepointInterval millis:
>>>>>>>>>>>> - This allows is_async_deflation_needed() to be
>>>>>>>>>>>> checked at
>>>>>>>>>>>> the same interval as GuaranteedSafepointInterval.
>>>>>>>>>>>> (default is 1000 millis/1 second)
>>>>>>>>>>>> - Once is_async_deflation_needed() has returned true, it
>>>>>>>>>>>> generally cannot return true for
>>>>>>>>>>>> AsyncDeflationInterval.
>>>>>>>>>>>> This is to prevent async deflation from swamping the
>>>>>>>>>>>> ServiceThread.
>>>>>>>>>>>> - The ServiceThread still handles async deflation of the
>>>>>>>>>>>> global
>>>>>>>>>>>> in-use list and now it also marks JavaThreads for async
>>>>>>>>>>>> deflation
>>>>>>>>>>>> of their in-use lists.
>>>>>>>>>>>> - The ServiceThread will check for async deflation work
>>>>>>>>>>>> every
>>>>>>>>>>>> GuaranteedSafepointInterval.
>>>>>>>>>>>> - A safepoint can still cause the ServiceThread to
>>>>>>>>>>>> check for
>>>>>>>>>>>> async deflation work via is_async_deflation_requested.
>>>>>>>>>>>> - Refactor code from
>>>>>>>>>>>> ObjectSynchronizer::is_cleanup_needed() into
>>>>>>>>>>>> monitors_used_above_threshold() and remove
>>>>>>>>>>>> is_cleanup_needed().
>>>>>>>>>>>> - In addition to System.gc(), the VM_Exit VM op and the
>>>>>>>>>>>> final
>>>>>>>>>>>> VMThread safepoint now set the
>>>>>>>>>>>> is_special_deflation_requested
>>>>>>>>>>>> flag to reduce the in-use monitor population that is
>>>>>>>>>>>> reported by
>>>>>>>>>>>> ObjectSynchronizer::log_in_use_monitor_details() at VM exit.
>>>>>>>>>>>>
>>>>>>>>>>>> Test update:
>>>>>>>>>>>> - test/hotspot/gtest/oops/test_markOop.cpp is updated to
>>>>>>>>>>>> work with
>>>>>>>>>>>> AsyncDeflateIdleMonitors.
>>>>>>>>>>>>
>>>>>>>>>>>> Collateral:
>>>>>>>>>>>> - Add/clarify/update some logging messages.
>>>>>>>>>>>>
>>>>>>>>>>>> Cleanup:
>>>>>>>>>>>> - Updated comments based on Karen's code review.
>>>>>>>>>>>> - Change 'special cleanup' -> 'special deflation' and
>>>>>>>>>>>> 'async cleanup' -> 'async deflation'.
>>>>>>>>>>>> - comment and function name changes
>>>>>>>>>>>> - Clarify MonitorUsedDeflationThreshold description;
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Main bug URL:
>>>>>>>>>>>>
>>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>>
>>>>>>>>>>>> The project is currently baselined on jdk-13+22.
>>>>>>>>>>>>
>>>>>>>>>>>> Here's the full webrev URL:
>>>>>>>>>>>>
>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/7-for-jdk13.full/
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Here's the incremental webrev URL:
>>>>>>>>>>>>
>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/7-for-jdk13.inc/
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> I have not updated the OpenJDK wiki to reflect the CR4
>>>>>>>>>>>> changes:
>>>>>>>>>>>>
>>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> The wiki doesn't say a whole lot about the async deflation
>>>>>>>>>>>> invocation
>>>>>>>>>>>> mechanism so I have to figure out how to add that content.
>>>>>>>>>>>>
>>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-8]
>>>>>>>>>>>> testing on
>>>>>>>>>>>> Oracle's usual set of platforms. My Solaris-X64 stress kit
>>>>>>>>>>>> run is
>>>>>>>>>>>> running now. Kitchensink8H on product, fastdebug, and
>>>>>>>>>>>> slowdebug bits
>>>>>>>>>>>> are running on Linux-X64, MacOSX and Solaris-X64. I still
>>>>>>>>>>>> have to run
>>>>>>>>>>>> my stress kit on Linux-X64. I still have to run the
>>>>>>>>>>>> SPECjbb2015
>>>>>>>>>>>> baseline and CR4 runs on Linux-X64, MacOSX and Solaris-X64.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks, in advance, for any questions, comments or
>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>
>>>>>>>>>>>> Dan
>>>>>>>>>>>>
>>>>>>>>>>>> On 5/6/19 11:52 AM, Daniel D. Daugherty wrote:
>>>>>>>>>>>>> Greetings,
>>>>>>>>>>>>>
>>>>>>>>>>>>> I had some discussions with Karen about a race that was in
>>>>>>>>>>>>> the
>>>>>>>>>>>>> ObjectMonitor::enter() code in CR2/v2.02/5-for-jdk13. This
>>>>>>>>>>>>> race was
>>>>>>>>>>>>> theoretical and I had no test failures due to it. The fix
>>>>>>>>>>>>> is pretty
>>>>>>>>>>>>> simple: remove the special case code for async deflation
>>>>>>>>>>>>> in the
>>>>>>>>>>>>> ObjectMonitor::enter() function and rely solely on the
>>>>>>>>>>>>> ref_count
>>>>>>>>>>>>> for ObjectMonitor::enter() protection.
>>>>>>>>>>>>>
>>>>>>>>>>>>> During those discussions Karen also floated the idea of
>>>>>>>>>>>>> using the
>>>>>>>>>>>>> ref_count field instead of the contentions field for the
>>>>>>>>>>>>> Async
>>>>>>>>>>>>> Monitor Deflation protocol. I decided to go ahead and code
>>>>>>>>>>>>> up that
>>>>>>>>>>>>> change and I have run it through the usual stress and
>>>>>>>>>>>>> Mach5 testing
>>>>>>>>>>>>> with no issues. It's also known as v2.03 (for those for
>>>>>>>>>>>>> with the
>>>>>>>>>>>>> patches) and as webrev/6-for-jdk13 (for those with webrev
>>>>>>>>>>>>> URLs).
>>>>>>>>>>>>> Sorry for all the names...
>>>>>>>>>>>>>
>>>>>>>>>>>>> Main bug URL:
>>>>>>>>>>>>>
>>>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>>>
>>>>>>>>>>>>> The project is currently baselined on jdk-13+18.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Here's the full webrev URL:
>>>>>>>>>>>>>
>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/6-for-jdk13.full/
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> Here's the incremental webrev URL:
>>>>>>>>>>>>>
>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/6-for-jdk13.inc/
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> I have also updated the OpenJDK wiki to reflect the CR3
>>>>>>>>>>>>> changes:
>>>>>>>>>>>>>
>>>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-8]
>>>>>>>>>>>>> testing on
>>>>>>>>>>>>> Oracle's usual set of platforms. My Solaris-X64 stress kit
>>>>>>>>>>>>> run had
>>>>>>>>>>>>> no issues. Kitchensink8H on product, fastdebug, and
>>>>>>>>>>>>> slowdebug bits
>>>>>>>>>>>>> had no failures on Linux-X64; MacOSX fastdebug and
>>>>>>>>>>>>> slowdebug and
>>>>>>>>>>>>> Solaris-X64 release had the usual "Too large time diff"
>>>>>>>>>>>>> complaints.
>>>>>>>>>>>>> 12 hour Inflate2 runs on product, fastdebug and slowdebug
>>>>>>>>>>>>> bits on
>>>>>>>>>>>>> Linux-X64, MacOSX and Solaris-X64 had no failures. My
>>>>>>>>>>>>> Linux-X64
>>>>>>>>>>>>> stress kit is running right now.
>>>>>>>>>>>>>
>>>>>>>>>>>>> I've done the SPECjbb2015 baseline and CR3 runs. I need to
>>>>>>>>>>>>> gather
>>>>>>>>>>>>> the results and analyze them.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks, in advance, for any questions, comments or
>>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Dan
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> On 4/25/19 12:38 PM, Daniel D. Daugherty wrote:
>>>>>>>>>>>>>> Greetings,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I have a small but important bug fix for the Async
>>>>>>>>>>>>>> Monitor Deflation
>>>>>>>>>>>>>> project ready to go. It's also known as v2.02 (for those
>>>>>>>>>>>>>> for with the
>>>>>>>>>>>>>> patches) and as webrev/5-for-jdk13 (for those with webrev
>>>>>>>>>>>>>> URLs). Sorry
>>>>>>>>>>>>>> for all the names...
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> JDK-8222295 was pushed to jdk/jdk two days ago so that
>>>>>>>>>>>>>> baseline patch
>>>>>>>>>>>>>> is out of our hair.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Main bug URL:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> The project is currently baselined on jdk-13+17.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Here's the full webrev URL:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/5-for-jdk13.full/
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Here's the incremental webrev URL (JDK-8153224):
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/5-for-jdk13.inc/
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I still have to update the OpenJDK wiki to reflect the
>>>>>>>>>>>>>> CR2 changes:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-6]
>>>>>>>>>>>>>> testing on
>>>>>>>>>>>>>> Oracle's usual set of platforms. Mach5 tier[7-8] is
>>>>>>>>>>>>>> running now.
>>>>>>>>>>>>>> My stress kit is running on Solaris-X64 now.
>>>>>>>>>>>>>> Kitchensink8H is running
>>>>>>>>>>>>>> now on product, fastdebug, and slowdebug bits on
>>>>>>>>>>>>>> Linux-X64, MacOSX
>>>>>>>>>>>>>> and Solaris-X64. 12 hour Inflate2 runs are running now on
>>>>>>>>>>>>>> product,
>>>>>>>>>>>>>> fastdebug and slowdebug bits on Linux-X64, MacOSX and
>>>>>>>>>>>>>> Solaris-X64.
>>>>>>>>>>>>>> I'll start my my stress kit on Linux-X64 sometime on
>>>>>>>>>>>>>> Sunday (after
>>>>>>>>>>>>>> my jdk-13+18 stress run is done).
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I'll do SPECjbb2015 baseline and CR2 runs after all the
>>>>>>>>>>>>>> stress
>>>>>>>>>>>>>> testing is done.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks, in advance, for any questions, comments or
>>>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Dan
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 4/19/19 11:58 AM, Daniel D. Daugherty wrote:
>>>>>>>>>>>>>>> Greetings,
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I finally have CR1 for the Async Monitor Deflation
>>>>>>>>>>>>>>> project ready to
>>>>>>>>>>>>>>> go. It's also known as v2.01 (for those for with the
>>>>>>>>>>>>>>> patches) and as
>>>>>>>>>>>>>>> webrev/4-for-jdk13 (for those with webrev URLs). Sorry
>>>>>>>>>>>>>>> for all the
>>>>>>>>>>>>>>> names...
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Main bug URL:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Baseline bug fixes URL:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> JDK-8222295 more baseline cleanups from Async
>>>>>>>>>>>>>>> Monitor Deflation project
>>>>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8222295
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> The project is currently baselined on jdk-13+15.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Here's the webrev for the latest baseline changes
>>>>>>>>>>>>>>> (JDK-8222295):
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/4-for-jdk13.8222295
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Here's the full webrev URL (JDK-8153224 only):
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/4-for-jdk13.full/
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Here's the incremental webrev URL (JDK-8153224):
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/4-for-jdk13.inc/
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> So I'm looking for reviews for both JDK-8222295 and the
>>>>>>>>>>>>>>> latest version
>>>>>>>>>>>>>>> of JDK-8153224...
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I still have to update the OpenJDK wiki to reflect the
>>>>>>>>>>>>>>> CR changes:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-3]
>>>>>>>>>>>>>>> testing on
>>>>>>>>>>>>>>> Oracle's usual set of platforms. Mach5 tier[4-6] is
>>>>>>>>>>>>>>> running now and
>>>>>>>>>>>>>>> Mach5 tier[78] will be run later today. My stress kit on
>>>>>>>>>>>>>>> Solaris-X64
>>>>>>>>>>>>>>> is running now. Linux-X64 stress testing will start on
>>>>>>>>>>>>>>> Sunday. I'm
>>>>>>>>>>>>>>> planning to do Kitchensink runs, SPECjbb2015 runs and my
>>>>>>>>>>>>>>> monitor
>>>>>>>>>>>>>>> inflation stress tests on Linux-X64, MacOSX and
>>>>>>>>>>>>>>> Solaris-X64.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Thanks, in advance, for any questions, comments or
>>>>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Dan
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On 3/24/19 9:57 AM, Daniel D. Daugherty wrote:
>>>>>>>>>>>>>>>> Greetings,
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Welcome to the OpenJDK review thread for my port of
>>>>>>>>>>>>>>>> Carsten's work on:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> JDK-8153224 Monitor deflation prolong safepoints
>>>>>>>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8153224
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Here's a link to the OpenJDK wiki that describes my port:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> https://wiki.openjdk.java.net/display/HotSpot/Async+Monitor+Deflation
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Here's the webrev URL:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dcubed/8153224-webrev/3-for-jdk13/
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Here's a link to Carsten's original webrev:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~cvarming/monitor_deflate_conc/0/
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Earlier versions of this patch have been through
>>>>>>>>>>>>>>>> several rounds of
>>>>>>>>>>>>>>>> preliminary review. Many thanks to Carsten, Coleen,
>>>>>>>>>>>>>>>> Robbin, and
>>>>>>>>>>>>>>>> Roman for their preliminary code review comments. A
>>>>>>>>>>>>>>>> very special
>>>>>>>>>>>>>>>> thanks to Robbin and Roman for building and testing the
>>>>>>>>>>>>>>>> patch in
>>>>>>>>>>>>>>>> their own environments (including specJBB2015).
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> This version of the patch has been thru Mach5 tier[1-8]
>>>>>>>>>>>>>>>> testing on
>>>>>>>>>>>>>>>> Oracle's usual set of platforms. Earlier versions have
>>>>>>>>>>>>>>>> been run
>>>>>>>>>>>>>>>> through my stress kit on my Linux-X64 and Solaris-X64
>>>>>>>>>>>>>>>> servers
>>>>>>>>>>>>>>>> (product, fastdebug, slowdebug).Earlier versions have
>>>>>>>>>>>>>>>> run Kitchensink
>>>>>>>>>>>>>>>> for 12 hours on MacOSX, Linux-X64 and Solaris-X64
>>>>>>>>>>>>>>>> (product, fastdebug
>>>>>>>>>>>>>>>> and slowdebug). Earlier versions have run my monitor
>>>>>>>>>>>>>>>> inflation stress
>>>>>>>>>>>>>>>> tests for 12 hours on MacOSX, Linux-X64 and Solaris-X64
>>>>>>>>>>>>>>>> (product,
>>>>>>>>>>>>>>>> fastdebug and slowdebug).
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> All of the testing done on earlier versions will be
>>>>>>>>>>>>>>>> redone on the
>>>>>>>>>>>>>>>> latest version of the patch.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Thanks, in advance, for any questions, comments or
>>>>>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Dan
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> P.S.
>>>>>>>>>>>>>>>> One subtest in
>>>>>>>>>>>>>>>> gc/g1/humongousObjects/TestHumongousClassLoader.java
>>>>>>>>>>>>>>>> is currently failing in -Xcomp mode on Win* only. I've
>>>>>>>>>>>>>>>> been trying
>>>>>>>>>>>>>>>> to characterize/analyze this failure for more than a
>>>>>>>>>>>>>>>> week now. At
>>>>>>>>>>>>>>>> this point I'm convinced that Async Monitor Deflation
>>>>>>>>>>>>>>>> is aggravating
>>>>>>>>>>>>>>>> an existing bug. However, I plan to have a better
>>>>>>>>>>>>>>>> handle on that
>>>>>>>>>>>>>>>> failure before these bits are pushed to the jdk/jdk repo.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>
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