RFR: 8065331: Add JVM trace events for failed allocations

Erik Helin erik.helin at oracle.com
Wed Apr 8 15:13:42 UTC 2015


On 2015-04-08, Marcus Larsson wrote:
> Hi again,
> 
> During offline discussions with Erik Helin we decided to skip the gc-attempt
> counter altogether, since this information had little value. Also, as the
> "Collect for allocation" event would always be accompanied by the (already
> existing) garbage collection events, this event is unnecessary and has been
> removed as well. Instead, to see allocations pending a particular GC, one
> can look at "Allocations requiring GC" events preceding the garbage
> collection event sent for that GC.
> 
> New (significantly smaller) webrev:
> http://cr.openjdk.java.net/~mlarsson/8065331/webrev.02/

Looks good to me, Reviewed.

Thanks,
Erik

> Thanks,
> Marcus
> 
> 
> On 04/02/2015 02:55 AM, Marcus Larsson wrote:
> >Hi Jon,
> >
> >Thank you for looking at this.
> >
> >The way I intended the gc count information to be useful is to indicate if/when allocations keep failing. Problematic allocations would then have a gc count higher than 1. It's not really critical that this is the exact total, as it's just an indication, so a partial GC count could work I guess. If you think it would be better I can take a look at how I can reduce the CR by being less precise with this counter.
> >
> >Thanks,
> >Marcus
> >
> >----- Original Message -----
> >From: jon.masamitsu at oracle.com
> >To: hotspot-gc-dev at openjdk.java.net
> >Sent: Wednesday, 1 April, 2015 4:44:30 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
> >Subject: Re: RFR: 8065331: Add JVM trace events for failed allocations
> >
> >Marcus,
> >
> >These changes are rather extensive and the CR is rather thin
> >on details.  How will the GC count information be useful?
> >Is it critical that it be the total GC count for failed allocation?
> >Could some partial GC count that does not require such
> >extensive changes be almost as useful?
> >
> >Thanks.
> >
> >Jon
> >
> >On 3/30/2015 3:54 PM, Marcus Larsson wrote:
> >>Ping!
> >>
> >>----- Original Message -----
> >>From: marcus.larsson at oracle.com
> >>To: hotspot-gc-dev at openjdk.java.net
> >>Sent: Tuesday, 24 March, 2015 7:35:08 AM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
> >>Subject: RFR: 8065331: Add JVM trace events for failed allocations
> >>
> >>Hi,
> >>
> >>Please review the following patch adding new trace events for allocations requiring GC, and GCs triggered by allocation. See the JEP for a description of these two new events.
> >>
> >>CR:
> >>https://bugs.openjdk.java.net/browse/JDK-8065331
> >>
> >>Webrev:
> >>http://cr.openjdk.java.net/~mlarsson/8065331/webrev.00/
> >>
> >>JEP:
> >>https://bugs.openjdk.java.net/browse/JDK-8060092
> >>
> >>Tests:
> >>jprt, jtreg
> >>
> >>Thanks,
> >>Marcus
> 


More information about the hotspot-gc-dev mailing list