Feedback requested: HotSpot GC logging improvements

Adam Hawthorne adamh at
Thu May 6 20:28:51 UTC 2010


On Thu, May 6, 2010 at 15:32, Tony Printezis <tony.printezis at>wrote:

> Hi all,
> A. Unification and improvement of -verbosegc / -XX:+PrintGCDetails output.

> Specific questions:
> - Is anyone really attached to the old -verbosegc output?

We aren't.

- Would anyone really hate having time stamps by default?

I'm in agreement with other folks; timestamps are okay, but date stamps by
default would be better.

- I know that a lot of folks have their own parsers for our current GC
> log formats. Would you be happy if we provided you with a (reliable!)
> parser for the new format in Java that you can easily adapt?

+1.  Or +10.

> B. Introducing "cyclic" GC logs.
> Specific questions:


> - Would people really hate it if HotSpot starts appending the GC log

 file name with a (zero-padded) sequence number? Maybe if N == 1 (the
> default), HotSpot will skip the sequence number and ignore S, i.e.,
> behave as it does today.

How many digits in the sequence?  Would that be configurable?

Overall, having this is better than not having it.

- To the people who have been asking for cyclic GC logs: is the sequence
> number scheme above good enough?
Much better than nothing at all for disk-conscious customers.



Adam Hawthorne
Software Engineer
BASIS International Ltd.
+1.505.345.5232 Phone
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