RFR (S): JDK-8077938: Remove TraceMarkSweep

Jon Masamitsu jon.masamitsu at oracle.com
Thu Apr 16 18:14:19 UTC 2015


The odd things you find when you really look :-)

Change looks good.

Jon


On 04/16/2015 02:29 AM, Bengt Rutisson wrote:
>
> Hi everyone,
>
> Could I have a couple of reviews for this small change?
>
> https://bugs.openjdk.java.net/browse/JDK-8077938
> http://cr.openjdk.java.net/~brutisso/8077938/webrev.00/
>
> The flag TraceMarkSweep logs the number for the phase in the mark 
> sweep code. This is pure debugging code that does not give much 
> information:
>
> $ java -XX:+UseSerialGC -XX:+TraceMarkSweep SysGC 10
>  1234 1234 1234 1234 1234 1234 1234 1234 1234 1234
>
> This does not help much even if combined with PrintGC:
>
> #1: [Full GC (System.gc()) 1234 310K->310K(497024K), 0,0125369 secs]
>
> or PrintGCDetails:
>
> #1: [Full GC (System.gc()) #1: [Tenured 1234: 310K->310K(342720K), 
> 0,0087471 secs] 310K->310K(497024K), [Metaspace: 
> 2832K->2832K(1056768K)], 0,0088441 secs] [Times: user=0,00 sys=0,00 
> real=0,01 secs]
>
> There are already trace events for the phases that include information 
> about the time for the phase and a more readable name. Thus, I think 
> we should remove this code.
>
> Thanks,
> Bengt



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