RFR(XS): 8210716: Detailed GC logging request misses some

[Kim Barrett]

> On Sep 29, 2018, at 3:19 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
>> On Sep 28, 2018, at 9:46 PM, Man Cao <manc at google.com> wrote:
>> 
>> Hi,
>> 
>> Could someone review this minor logging tag change for ParallelGC? It avoids missing log messages with -Xlog:gc*=debug and -Xlog:gc*=trace.
>> 
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8210716
>> Webrev: http://cr.openjdk.java.net/~manc/8210716/webrev.00/
>> 
>> PS: I'd need someone help me push it as I just became an Author.
>> 
>> Thanks,
>> Man
> 
> All other uses of the "ergo" tag in gc logging place it as the second
> tag, e.g. "(gc, ergo, ...)" or "(gc, ergo)".  Not that the order
> matters for logging control, but consistency can help with searching
> and pattern matching while reading.

FYI, it turns out the tag ordering does need to be consistent.  There is a gtest that complains if they aren’t. 

[ RUN      ] LogTagSet.duplicates_test
test/hotspot/gtest/logging/test_logTagSet.cpp:169: Failure
Failed
duplicate LogTagSets found: 'gc,ergo,heap' vs 'gc,heap,ergo' (tags must always be specified in the same order for each tagset)
[  FAILED  ] LogTagSet.duplicates_test (1 ms)

Was the original patch run through dev-submit? I think that should have failed because of the failing gtest.