RFR(L) 8153224 Monitor deflation prolong safepoints (CR10/v2.10/13-for-jdk15)
Daniel D. Daugherty
daniel.daugherty at oracle.com
Wed Feb 26 22:22:02 UTC 2020
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.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
-------------- next part --------------
Functional:
- items from meeting with Erik O, Robbin, Jesper and Mary:
- backout HandshakeAfterDeflateIdleMonitors option and always do a
handshake after deflation
- backout C2 ref_count changes since handshake after deflation
closes the race
- items from the hunt for 8230249:
- backout marking the ObjectMonitor::_header field
- log when cas_set_mark() in install_displaced_markword_in_object()
fails due to a race
- call try_set_owner_from(DEFLATER_MARKER, NULL) as needed to clear
the owner field
Test update:
- backout workaround in test/jdk/java/rmi/server/UnicastRemoteObject/
unexportObject/UnexportLeak.java since ServiceThread deflation
should solve that problem
Cleanup:
- rename set_om_ptr_if_safe() to save_om_ptr_if_safe()
- delete unused ref_count_offset_in_bytes()
- fix pad size error in print_debug_style_on(()
- reformat some code with really long lines
- clarify comments
- copyright year changes (a new year has arrived!)
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