RFR (S): JDK-8077938: Remove TraceMarkSweep

Bengt Rutisson bengt.rutisson at oracle.com
Thu Apr 16 09:29:55 UTC 2015

Hi everyone,

Could I have a couple of reviews for this small change?


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.


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