Please Review (S): CR 6782663: Data produced by PrintGCApplicationConcurrentTime and PrintGCApplicationStoppedTime is not accurate

[john cuthbertson - Sun Microsystems]

Hi Everyone,

Can I have a couple of volunteers look over the attached changes for 
this CR? The changes can be found at:

http://cr.openjdk.java.net/~johnc/6782663/webrev.00/

The issue here was that the code that was printing this information was 
only executed for synchronous safepoints and ignored forced safepoints. 
The user would see missing chunks of time (especially with also 
displaying GC time stamps) giving the impression that the JVM and app 
were idle. I was able to see this in the first few minutes of SPECjbb2005.

The simple solution was to move the printing into the routines that 
record safepoint starts and ends, capturing guaranteed safepoints. I 
have also changed the names of the flags to more accurately describe 
that GCs are not the only things we take a safepoint for (and deprecated 
the old flag names).

With these changes I see a delta between (application time + safepoint 
time) and the GC timestamp of around 0.1s instead of around 5 and 7 
seconds previously.

Testing: SPECjbb2005 (exhibited behavior), IBM UK's own evaluation, and 
JPRT.

Thanks,

JohnC