RFR(XS): 8008188: Add regression test for 8005875

John Cuthbertson john.cuthbertson at oracle.com
Thu Feb 14 18:50:09 UTC 2013

Hi Bengt, Leonid,

On 2/14/2013 4:47 AM, Bengt Rutisson wrote:
> Leonid,
> Yes, this is an interesting problem. If the buffer for the 
> OutputAnalyzer gets full before the jmap call returns we will have a 
> deadlock.
> Would you suggest that the test should spawn two processes? How do 
> they do the handshaking to find out when it is safe to do a jmap call 
> from one to the other?

As Mikael Gerdin has pointed out there are already a bunch of NMT 
regression tests that call jcmd on themselves and I just followed the 
guidelines given in Christian Tornqvist's wiki. If this is an issue then 
all of these NMT tests should be removed and this mechanism should also 
be removed.

Also the output of the jcmd is not that important - it's the fact that 
the test didn't crash. So if there's a way avoid the potential deadlock 
by disregarding the output - so be it.

> Looking at this test again reminded me of a few more minor things:
> * It would be good if the test had the "@key gc" tag that I am just 
> about to add. See:
> http://cr.openjdk.java.net/~brutisso/8006398/webrev.01/

OK. Sure.

> * You don't need -XX:+IgnoreUnrecognizedVMOptions in the @run command

Why not? What about running on a platform where UseG1GC is not currently 
supported and the flag gives an error?

> * The test is in a directory called 8005875/. I again think this is 
> obsolete if we use the @bug tag. I would prefer to name the folder 
> something meaningful.

OK. But IMO the bug ID is meaningful. Is it any more meaningful than 
TestJcmdG1AndZeroPGCT? I'm not sure. Suggest a name that you find more 

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