RFR (M): JDK-8043607: Add a GC id as a log decoration similar to PrintGCTimeStamps

[Thomas Schatzl]

Hi Bengt,

On Wed, 2014-06-04 at 17:06 +0200, Bengt Rutisson wrote:
> Hi Erik,
> 
> On 5/28/14 2:29 PM, Erik Helin wrote:
> > Hi Bengt,
> >
> > just a first quick general comment: would it make sense for GCId to be
> > in its own file or class, so the GC logging don't have to depend on
> > the GC trace framework?
> 
> Good point.
> 
> Here is an updated webrev where I separeted out GCId to its own file:
> http://cr.openjdk.java.net/~brutisso/8043607/webrev.02/
> 
> Here's just the diff compared to the earlier version:
> http://cr.openjdk.java.net/~brutisso/8043607/webrev.01-02.diff/
> 
> Jesper, the updated webrev also contains the spelling mistake you 
> noticed. Thanks for catching that!
> 

 two minor comments:

- is it useful to check whether we are at a safepoint and running in the
VM thread when incrementing the gc id?

- also it would be nice to have some test case that checks for presence
of the numbers in log messages (and their absence if disabled).

Thanks,
  Thomas