RFR (XS): 8200730: Fix debug=gc+phases time tracking in Remark and Cleanup

[Stefan Johansson]

Hi Thomas,

On 2018-04-16 13:14, Thomas Schatzl wrote:
> Hi all,
> 
>    ping for any reviewer...
> 
> Thanks,
>    Thomas
> 
> On Wed, 2018-04-04 at 14:26 +0200, Thomas Schatzl wrote:
>> Hi all,
>>
>>    can I have reviews to let the recently introduced timing
>> measurements
>> in Remark and Cleanup pauses actually show useful numbers?
>>
>> The problem is that the GCTraceTime instances were not assigned to a
>> variable inside a scope so the compiler immediately destructed it,
>> always giving "0.000ms" lengths.
>>
>> Also added to use the gc timer to these lines for JFR support.
>>
>> I would like to think this is a trivial change.
>>
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8200730
>> Webrev:
>> http://cr.openjdk.java.net/~tschatzl/8200730/webrev
Sorry for missing this one :)

Thanks for fixing this. Two things:
src/hotspot/share/gc/g1/g1ConcurrentMark.cpp
1994     GCTraceTime(Debug, gc)("Clear Next Bitmap");

This line should to be changed as well.
---

The second thing is a partly pre-existing problem and I suggest you fix 
all occurrences in this file. The name "trace" is a bit misleading when 
the debug-level is "Debug", which is the case for all GCTraceTime in 
this file. I would prefer using "debug", like on this line:
1654     GCTraceTime(Debug, gc, phases) debug("Weak Processing", 
_gc_timer_cm);
-----

Thanks,
Stefan

>> Testing:
>> manual verification that the shown numbers are sane
>>
>> Thanks,
>>    Thomas
>>
>