RFR rev1 (M): 8078556: Runtime: implement ranges (optionally constraints) for those flags that have them missing (original) (raw)

gerard ziemski gerard.ziemski at oracle.com
Tue Oct 13 17:19:10 UTC 2015

hi Dmitry,

Excellent findings. I lost a few changes due to the sync-up to TOT to get the GC flag fixes.

On 10/13/2015 11:03 AM, Dmitry Dmitriev wrote:

Hi Gerard,

Thank you for fixing issues from revision 0, overall looks good, but I found that some of these issues are still exist. Here are few small issues: 1) BiasedLockingBulkRevokeThresholdFunc constraint function still have(line 97, commandLineFlagConstraintsRuntime.cpp) "(double)value/(double)BiasedLockingDecayTime >= 0.1" instead of > 0.1 as in corrected BiasedLockingDecayTimeFunc constraint function.

Redone.

2) Following code still exist in hotspot/src/share/vm/runtime/safepoint.cpp module(lines 1055-1057): if (PrintSafepointStatisticsCount <= 0) { fatal("Wrong PrintSafepointStatisticsCount"); } PrintSafepointStatisticsCount flag have range (1, maxintx), thus as I remember we agreed that this code is redundant. Can you please remove them?

Redone.

3) You correct MaxJavaStackTraceDepth max range to maxintx/2 according to my comment from previous review, but not change maxintx to maxjint. This flag is assigned to int variables and using maxintx can lead to overflow. Thus, I think that maxjint should be instead of maxintx.

This I think I missed, but you are right, on 64bit intx is 8 bytes, but int is 4, so we need max_jint (max_int) here.

4) I don't see changes to the TestOptionsWithRanges.java in rev2. It is possible that these changes are lost in sync with GC ranges or these changes are not more needed?

Redone.

I will need to re-submit RBT and JPRT to make 100% sure all is right here.

Thank you for the review!

I don't need to see another webrev for that.

Thank you, Dmitry On 13.10.2015 17:26, gerard ziemski wrote: Thank you Yumin, Jiangli for the feedback.

For the time being I'm going to leave AttachListenerTimeout range as is. It was defined by Staffan Larsen and we can always tweak the value later if we have a good reason. I agree that the value looks awkward. The value is exactly 35 min, and why that is would be a question for Staffan. I have updated the webrev http://cr.openjdk.java.net/~gziemski/8078556rev2 that only has 3 differences from rev1: #1 SharedSymbolTableBucketSize range min is now 2 [Jiangli] #2 Updated INITIALCONSTRAINTSSIZE 45 [Dmitry, merged with GC flags changes] #3 Updated INITIALRANGESSIZES 204 [Dmitry, merged with GC flags changes]

Testing with the new value passes JPRT and RBT tests. Dmitry, Coleen, can I please have your final reviews? cheers On 10/12/2015 10:41 PM, Yumin Qi wrote: Hi, Gerard I am not the definer for ShareTableBucketSize --- Jangli first checked int code for its definition: changeset: 7561:05c08ab3cf65 parent: 7559:47ffd05828f9 user: jiangli date: Wed Dec 17 23:34:52 2014 -0500 summary: 8059510: Compact symbol table layout inside shared archive. changeset: 7561:05c08ab3cf65 parent: 7559:47ffd05828f9 user: jiangli date: Wed Dec 17 23:34:52 2014 -0500 summary: 8059510: Compact symbol table layout inside shared archive.

BTW, I only have one minor comment: *src/os/aix/vm/globalsaix.hpp: **productpd(intx, AttachListenerTimeout, * *"Timeout in ms the attach listener waits for a request") * *+ range(0, 2147483) \ This is about 35 minutes. But the number looks awkward. I am ok if you keep it, better to change to a reasonable reading symbol. Thanks Yumin *

On 10/9/15, 11:47 AM, gerard ziemski wrote: (resending, fixed webrev link) hi all, Please review this rev1 change that implements ranges and constraint for runtime flags. The purpose of the ranges is to define valid ranges, that are guaranteed to be accepted and work when instantiating a VM. The VM is allowed to exit with an exception due to out of OS resources (like memory), but it may not assert or prematurely exit with an error that produces hserr and/or dump core. Summary of changes since rev0: #1 Punted the following flags: SharedBaseAddress SharedMiscCodeSize SharedMiscDataSize SharedReadOnlySize SharedReadWriteSize to task JDK-8138983 since their ranges are nontrivial [Coleen, Jianghli] #2. Removed unused "Arguments::getdefaultheapbaseminaddress" [Coleen] #3. Users may need to use "TraceRedefineClasses" with their own custom events, so changed the max value to 0XFFFFFFFF [Dmitry, Dan] #4. All other feedback from Dmitry implemented, see below #5. PrintSafepointStatisticsTimeout and SafepointtimeoutDelat max value is LP64ONLY(maxintx/MICROUNITS) NOTLP64(maxintx) because intx is 4bytes on 32bits architectures, so dividing it by MICROUNITS would bring the value below default. I did, however, make sure to upcast the values to jlong, so on 32bit they become 8byte long long, and so no overflow will occur when multiplying by MICROUNITS. #6. GuaranteedSafepointInterval range(0, maxintx) asserts (overflows) on Windows64 (maxintx on 64bit is 0x7FFFFFFFFFFFFFFF), so I changed the range max to maxjint (ie. 0x7FFFFFFF) which is roughly 25 days The following flags had their ranges defined by the the domain experts: AttachListenerTimeout: Staffan Larsen BiasedLockingBulkRebiasThreshold: Marcus Larsson BiasedLockingBulkRevokeThreshold: Marcus Larsson BiasedLockingDecayTime: Marcus Larsson BiasedLockingStartupDelay: Marcus Larsson SharedSymbolTableBucketSize: Yumin Qi StackShadowPages: Coleen Phillimore, Frederic Parain For the rest of the flags, I looked at the existing code that was using them and also did local tests: DeferPollingPageLoopCount DeferThrSuspendLoopCount GuaranteedSafepointInterval HeapBaseMinAddress InitialBootClassLoaderMetaspaceSize JavaPriority10ToOSPriority JavaPriority1ToOSPriority JavaPriority2ToOSPriority JavaPriority3ToOSPriority JavaPriority4ToOSPriority JavaPriority5ToOSPriority JavaPriority6ToOSPriority JavaPriority7ToOSPriority JavaPriority8ToOSPriority JavaPriority9ToOSPriority MallocMaxTestWords MallocVerifyInterval MallocVerifyStart MaxDirectMemorySize MaxJNILocalCapacity MaxJavaStackTraceDepth MaxRAM MinPassesBeforeFlush PerfDataMemorySize PerfDataSamplingInterval PerfMaxStringConstLength PrintSafepointStatisticsCount PrintSafepointStatisticsTimeout ProfileIntervalsTicks RTMRetryCount SafepointSpinBeforeYield SafepointTimeoutDelay SelfDestructTimer SuspendRetryCount SuspendRetryDelay ThreadSafetyMargin ThreadStackSize TraceRedefineClasses VMThreadPriority VMThreadStackSize The change passes “JPRT -testset hotspot”, “RBT hotspot/test/runtime/CommandLine” and “RBT testlist,noncolo.testlist --add-tonga-keyword quick” References: bugid: https://bugs.openjdk.java.net/browse/JDK-8078556 webrev: http://cr.openjdk.java.net/~gziemski/8078556rev1 Followup issues: https://bugs.openjdk.java.net/browse/JDK-8133564 "Runtime - 2nd followup to JDK-8059557" https://bugs.openjdk.java.net/browse/JDK-8136766 "Enable ThreadStackSize range test” https://bugs.openjdk.java.net/browse/JDK-8134691 "CommandLineFlagConstraint::AtParse is not useful and not what we need" https://bugs.openjdk.java.net/browse/JDK-8138983 "Runtime: implement ranges for Shared*** flags" Thank you.

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