RFR: 8191821: Finer granularity for GC verification
stefan.johansson at oracle.com
Wed Nov 29 11:39:44 UTC 2017
Thanks for the review Poonam,
Update webrevs with your and Sangheons comments:
On 2017-11-28 23:17, Poonam Parhar wrote:
> Hello Stefan,
> The changes look good! Thanks for implementing this enhancement.
> One observation:
> gcArguments.cpp: if we use VerifyGCType with the collectors that
> currently don't support it, passing it multiple comma separated
> strings, then parse_verification_type() will print this warning
> message "VerifyGCType is not supported by this collector." for all the
> strings. It would be better to break out from the while loop in
> post_heap_initialize() if the collector does not support this option.
> On 11/28/2017 8:25 AM, Stefan Johansson wrote:
>> Please review this change for enhancement:
>> Heap verification is a very good way to track down GC bugs, but it
>> comes with a lot of overhead. Using VerifyBeforeGC, VerifyDuringGC
>> and VerifyAfterGC often slows down the execution more than is needed
>> since we sometimes only want to verify certain types of GCs. This
>> change adds this feature for G1 by adding a new diagnostic flag
>> VerifyGCType. The new flag currently only works with G1 but can
>> easily be added for more GCs if needed. The type of the flag is
>> ccstrlist which means the option can be used multiple times to allow
>> more than one type to be verified. The types available for G1 is,
>> young, mixed, remark, cleanup and full. If the flag is not specified
>> all GCs are verified.
>> Note that Verify/Before/After/During/GC is still needed to decide
>> what to verify, VerifyGCType only describes when.
>> * Added new Gtest for G1HeapVerifier functionality.
>> * Added new Jtreg test for basic command line functionality.
>> * Executed Jtreg tests through mach5 to make sure it passes on all
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